'loculus' originates from Latin, specifically the word 'loculus,' where 'locus' meant 'place' and the diminutive suffix '-ulus' meant 'small' (so 'small place').

'loculus' passed from classical Latin into Late/Medieval Latin and was adopted into English primarily in learned and scientific contexts (medical, biological, archaeological) as 'loculus.'

Initially, it meant 'little place' in a general sense, but over time it became specialized to mean 'a small compartment, cell, or niche' in scientific and archaeological usage.