Words starting with O — 407 entries

The 407 dictionary words that begin with the letter O, in alphabetical order, each with its first definition. Accents do not affect filing: an accented initial is shelved under its base letter.

• oy1 senseAn exclamation typically expressing mild frustration or expressing feelings of uncertainty or concern.
• oyster8 sensesAny of certain marine bivalve mollusks, especially those of the family Ostreidae (the true oysters), usually found adhering to rocks or other fixed…
• Oyster1 senseA surname.
• Oz6 sensesAn unreal, magical realm.
• OZ1 senseAn ounce (especially of marijuana or other drugs).
• ozone3 sensesAn allotrope of oxygen (symbol O₃) having three atoms in the molecule instead of the usual two; it is a toxic gas, generated from oxygen by…
• Ozzy3 sensesA male given name.