Luke 2:21

The verb συλλαμβάνω, primarily means "to seize, gather, arrest, apprehend, or rally troops." Idiomatically, it might be used to mean "comprehend" or specially as a metaphor to describe conception, as the womb was thought to "enclose" or "seize" the fertilizing seed (Arist. HA 582a19, GA 727b8; Hipp. Aph. 5.46).

However, the more standard Greek term for "to conceive" was κύω, with its derivatives κύησις (pregnancy/conception) and κυοφορέω (to be pregnant), but not used in the NT.