'Concept' is Latin for 'something seized' — understanding is grasping, an idea caught by the mind.
From Latin 'conceptus' (a collecting, gathering; conception, thought; the act of conceiving), past participle of 'concipere' (to take in completely, to conceive), composed of 'con-' (together, completely) + 'capere' (to take, to seize), from PIE *keh₂p- (to grasp). The literal sense is 'taken together' or 'fully grasped' — a concept is an idea completely seized and held by the mind. The metaphor of understanding as physical grasping is ancient and cross-linguistic: English 'grasp' is used mentally, German 'begreifen' (to comprehend) literally means
The word 'conceive' uses the same root for both pregnancy and ideas — Latin 'concipere' meant both 'to become pregnant' (to take in seed) and 'to form an idea in the mind' (to take in a thought). English preserves this double meaning: you can conceive a child and conceive a plan. The metaphor equates forming an idea with the physical act