'apse-shaped' originates from Modern English, specifically the compound of 'apse' and 'shaped', where 'apse' ultimately meant 'arch' or 'vault' (from earlier languages) and 'shaped' means 'formed' or 'having the form of'.

'apse' changed from Latin 'apsis' and Greek 'apsis' (ᾰ́ψις) meaning 'arch, vault', and entered English via Medieval/Old French and Late Latin; 'shape' comes from Old English 'gesceap'/'sceap' (meaning 'form, creation'), which developed into Modern English 'shape'. The compound 'apse-shaped' is a modern English formation combining these elements.

Initially, 'apse' referred specifically to an architectural arch or vaulted recess; over time, in compounds like 'apse-shaped' it came to mean 'having the form of an apse'—i.e., shaped like that architectural feature.