An oil is any neutral, nonpolar chemical substance that is a viscous liquid at ambient temperatures and is both hydrophobic (immiscible with water, literally "water fearing") and lipophilic (miscible with other oils, literally "fat loving"). Oils have a high carbon and hydrogen content and are usually flammable and slippery.

The langues d'oïl ( French: ), or oïl languages (also in ), are a dialect continuum that includes standard French and its closest autochthonous relatives spoken today in the northern half of France, southern Belgium, and the Channel Islands. They belong to the larger Gallo-Romance languages, which also cover most of east-central (Arpitania) and southern France (Occitania), northern Italy and eastern Spain (Catalan Countries), although some linguists place Catalan into the Ibero-Romance grouping instead.

Oil is any of a number of nonpolar, hydrophobic, and viscous liquids.

This article is about the Upton Sinclair novel. For the substance, see oil.

Oil! is a novel by Upton Sinclair published in 1927 told as a third person narrative, with only the opening pages written in the second person. The book was written in the context of the Harding administration's Teapot Dome Scandal and takes place in Southern California. It is a social and political satire skewering the human foibles of all its characters.