(Internet, informal, humorous) Obligatory; prepended to the name of a topic being mentioned to avoid accusations of being off-topic.

(medicine) Observation(s) (blood pressure, temperature, etc).

(slang) police observation / An observation hut.

plural of ob

(in listing dates of death) Died.

Incidentally.

(music) Oboe(s).

The son of Ruth and Boaz, father of Jesse and grandfather of David, grandson of Naomi. / A male given name from Hebrew of biblical origin.

plural of double obelus

(uncountable, informal, medicine, initialism, acronym) Obstetrics and gynecology. / (countable, initialism, acronym) A physician in these specialties; an obstetrician-gynecologist.