fossil oil fossilogy • fossilological · · · Info · Definitions · Synonyms · Characters · · fossil oil · · Text Common · · Latin · · Scripts 10 · · Length 3 · · Syllables Definitions · · · (noun) a dark oil consisting mainly of hydrocarbons. Synonyms: petroleum, crude oil, crude, rock oil, fossil oil, oil. · · Noun Definition 1 Synonyms · · · petroleum · · Synonym 1 crude oil · · Synonym 2 crude · · Synonym 3 rock oil · · Synonym 4 oil · · Synonym 5 Characters · · space U+0020 f latin small letter f U+0066 i latin small letter i U+0069 l latin small letter l U+006C o latin small letter o U+006F s latin small letter s U+0073