18-letter words that end in or
- peasant proprietor — a peasant who owns land, especially the land he or she tills.
- peppermint camphor — menthol.
- pneumatic conveyor — a tube through which powdered or granular material, such as cement, grain, etc is transported by a flow of air
- protease inhibitor — a drug that inhibits the action of protease, especially any of a class of antiviral drugs that prevent the cleavage and replication of HIV proteins.
- quarry-tiled floor — a floor covered with square or diamond-shaped unglazed floor tiles
- sentence connector — a word or phrase that introduces a clause or sentence and serves as a transition between it and a previous clause or sentence, as for example also in I'm buying eggs and also I'm looking for a dessert for tonight. It may be preceded by a coordinating conjunction such as and in the above example
- sindbad the sailor — (in The Arabian Nights' Entertainments), a wealthy citizen of Baghdad who relates the adventures of his seven wonderful voyages.
- special prosecutor — (formerly) an independent counsel.
- stand-by generator — an electrical system which operates automatically in case the usual system malfunctions
- standoff insulator — a type of insulator that supports an electrical conductor at a distance from other elements or surfaces.
- student councillor — a student who is a member of a council or body representing the interests of students at a school, university or college
- turbine ventilator — a ventilator, usually mounted on the roof of a building, deck of a ship, etc., having at its head a globular, vaned rotor that is rotated by the wind, conveying air through a duct to and from a chamber below.
- visiting professor — a professor from another institution invited to teach at a university or college for a limited period, usually for a semester or one academic year.