Sojourn comes from Old French sojorner, sejorner ('to stay, dwell'), from Vulgar Latin *subdiurnare, from Latin sub- ('under') + Late Latin diurnum ('day'), from diēs ('day'). The historical chain includes Old French sojorner, Latin diurnum, and Latin diēs. Older glosses in the chain include "to stay, dwell", "under", and "day", which help explain the semantic range of the modern word. Morphologically, sojourn is best read as compound and borrowing, yielding an English noun and verb shaped by both form history and later usage. In current English it functions as a noun and verb, with the sense "a temporary stay in a place". English derivatives include sojourner. The result is an English noun and verb whose etymology preserves the older forms while supporting the word's specialized modern meaning.