early 14c., "act of conceiving," from Old French concepcion (Modern French conception) "conception, grasp, comprehension," from Latin conceptionem (nominative conceptio) "a comprehending, conception," noun of action from stem of concipere (see conceive). Originally in the womb sense (also with reference to Conception Day in the Church calendar); mental sense "process of forming concepts" is late 14c. Meaning "that which is conceived in the mind" is from 1520s; "general notion" is from 1785.