'loc' (plural 'locs') originates from Old English, specifically the word 'locc', where 'locc' meant 'lock (of hair)'. In modern usage the spelling 'loc/locs' has been adopted as an alternative form (influenced by Caribbean English/Rastafari usage) to refer to dreadlocks. Separately, 'LOC' is a modern English acronym for 'lines of code', and its informal plural may be written 'locs'.

'loc' changed from Old English word 'locc' and through Middle/Modern English 'lock'. The modern spelling 'loc' and plural 'locs' emerged in the 20th century in reference to the hairstyle. Independently, the acronym 'LOC' arose in computing in the mid-20th century from the phrase 'lines of code' and is sometimes pluralized informally as 'locs'.

Initially it meant 'lock (of hair)'; over time one meaning persisted as the specific hairstyle 'dreadlock' (giving 'loc/locs') while a separate, newer sense developed from the acronym 'LOC' meaning 'lines of code'.