This glossary brings together key concepts from Natural Sciences and connects them directly to my passion for Neuroscience and how the brain works. To keep everything accurate and complete, each term includes its part of speech, sentence-case definitions found by using Google Search (define + [term]), French translations, and text-to-speech audio models. Also, I've included authentic sentences example from the Lextutor Concordancer along with images from Wikimedia Commons to show how these terms actually work in real scientific contexts.
action potential
noun
A quick, temporary change in the electrical voltage across a cell membrane when a neuron or muscle cell fires.
Example: Influx of Ca 2+ ions causes opening of Ca 2+ gated K+ ion channels and subsequently depolarisation of the membrane, thus the generation of an action potential.
fr: potentiel d'action
brain
noun
The main organ inside the head that controls all body functions, thoughts, memory, feelings, and physical activity.
Example: How anything physical - a brain - should be able to support a mental life is beyond the reach not only of our science but of our imagination.
fr: cerveau
correlation
noun
A statistical measure that describes the connection or relationship between two or more variables.
Example: Regressions showed a significant negative correlation between growth rates and initial GDP.
fr: corrélation
derivative
noun
The limit of the ratio of the change in a function to the corresponding change in its independent variable as the latter change approaches zero.
Example: This is interesting in itself; as such a limit does not necessarily exist, we must entertain the possibility that some functions may not even admit a derivative.
fr: dérivée
enzyme
noun
Specialized proteins that act as biological catalysts to speed up chemical reactions in living organisms without being used up.
Example: The inhibition of the enzyme by very low concentrations of lanthanum ion is probably the strongest known biological effect of rare earth salts.
fr: enzyme
equilibrium
noun
A state of balance where opposing forces, influences, or actions cancel each other out.
Example: Indeed, nobody yet knows what a "natural" or "equilibrium" level of fertility may be in such societies.
fr: équilibre
exponential
adjective
A process or increase that becomes faster and faster as the size of something grows.
Example: While our improved calculation still experiences super-exponential growth, our improvements enable us to solve much larger problems than before.
fr: exponentielle
ion channel
noun
Specialized protein pores in cell membranes that let charged ions move in and out of cells.
Example: In addition, calcium activates an ion channel facilitating the efflux of chloride ions out of the cell.
fr: canal ionique
nerve impulse
noun
An electrical signal that travels along neurons to carry messages throughout the body. It allows the brain, spinal cord, and nerves to communicate quickly and precisely. Nerve impulses begin when sensory receptors detect a stimulus such as heat, pressure, or light...
Example: It is impossible to tell, from the physical attributes of a nerve impulse, whether it is conveying information about light, about sound or about smell.
fr: flux nerveux
neuron
noun
A specialized cell that transmits nerve impulses (electrical and chemical signals) through the nervous system.
Example: The data collected from the human neuron culture suggests the ability to study not only the electrical communication among the cultured neurons, but also allow examination of corresponding neurotransmitter releases.
fr: neurone
neuroplasticity
noun
Refers to your brain’s ability to absorb information and evolve to manage new challenges.
Example: Adolescence is a time of high neuroplasticity in which many lifelong habits, good and bad, are formed.
—
Keith Humphreys, The Atlantic, 2 Feb. 2026.
fr: neuroplasticité
neurotransmitter
noun
A chemical messenger that carries signals from one nerve cell to the next target cell across a tiny gap called a synapse.
Example: The data collected from the human neuron culture suggests the ability to study not only the electrical communication among the cultured neurons, but also allow examination of corresponding neurotransmitter releases.
fr: neurotransmetteur
optimization
noun
Finding the highest (maximum) or lowest (minimum) value of a function. This uses variables and fixed rules called constraints.
Example: In this thesis an optimization algorithm based on these ideas is demonstrated in 1 and 2-dimensions, for visualization, and then applied to the problem of factoring biprimes of up to 12 bits, and 4- and 5-City Travelling Salesman problems.
fr: optimisation
pH
noun
A measure of acidity and alkalinity of a solution that is a number on a scale on which a value of 7 represents neutrality and lower numbers indicate increasing acidity and higher numbers increasing alkalinity and on which each unit of change represents a tenfold change in acidity or alkalinity and that is the negative logarithm of the effective hydrogen-ion concentration or hydrogen-ion activity in gram equivalents per liter of the solution.
Example: The basal pH in the stomachs of owls are commonly in the range of 2.2 to 2.5, whereas that of falcons and eagles is 1.3 to 1.8.
fr: pH
probability
noun
A number from 0 to 1 that measures how likely an event is to occur.
Example: Risk is calculated based upon the formula Risk = probability * Damage Potential where probability and Damage Potential are ranked on a scale of 1-10, where 1 is very unlikely minimal damage and 10 is certainty catastrophic damage.
fr: probabilité
refraction
noun
The bending or change in direction of a wave—such as light, sound, or water—when it passes from one material into another at an angle. This happens because the wave changes its speed when it enters a new medium with a different density.
Example: As shear waves move with a velocity less than that of the longitudinal wave then according to Snell's Law the refraction angle will be less than the refraction angle for the longitudinal wave.
fr: réfraction
synapse
noun
A region where nerve impulses are transmitted and received, encompassing the axon terminal of a neuron that releases neurotransmitters in response to an impulse, an extremely small gap across which the neurotransmitters travel, and the adjacent membrane of an axon, dendrite, or muscle or gland cell with the appropriate receptor molecules for picking up the neurotransmitters.
Example: Over time, even their brain cells, synapses, blood flow and nervous systems start to be impaired.
—
Ramin Skibba, Newsweek, 18 Apr. 2017.
fr: synapse
torque
noun
The rotational or twisting equivalent of linear force that causes an object to turn around an axis or pivot point.
Example: It is assumed that the gyros are designed with electrical torquers so that a torque can be applied about their output axes.
fr: moment de torsion
variance
noun
The state of being different or changing, and in statistics, it measures how far a set of numbers spreads out from the average value.
Example: The mean value is a measure of location and the variance 2 is a measure of dispersion.
fr: variance
velocity
noun
The speed of an object moving in a specific direction.
Example: This allows the mechanism to be evaluated for any crank angle, velocity, acceleration or force by changing the initial input values.
