'haploid' originates from Greek, specifically the word 'haploos', where 'haploos' meant 'single', combined with the suffix '-oid' from Greek 'oeidēs' meaning 'form' or 'likeness'.

'haploid' was coined in scientific usage (New Latin/Germanic scientific literature) in the late 19th to early 20th century from Greek roots and entered modern English as the technical biological term 'haploid'.

Initially it carried the general sense of 'single' or 'single form', but over time it evolved into the specialized biological meaning 'having a single set of chromosomes'.