[off day] {n. phr.} A period when one is not functioning […]

[offshoot] {n.} A derivative; a side product. * /The discovery of […]

[old boy] or [old chap] {n.}, {chiefly British} One of the […]

[old boy network] {n. phr.} A system whereby men who went […]

[old college try] {n. phr.} An attempt to win a favor […]

[old country] {n. phr.} Primarily Europe, but also any country other […]

[old flame] {n. phr.} An erstwhile lover. * /Did you know […]

[old guard] {n. phr.} People whose ideas may be out of […]

[old hand] {n. phr.} An experienced and highly skilled expert at […]

[old maid] {n. phr.} A spinster; a woman who has never […]