petroleum petroleous • petrolic · · · Info · Definitions · Synonyms · Characters · · petroleum · · Text Latin · · Script 9 · · Length Definitions · · · (noun) a dark oil consisting mainly of hydrocarbons. Synonyms: crude oil, crude, rock oil, fossil oil, oil. · · Noun Definition 1 Synonyms · · · crude oil · · Synonym 1 crude · · Synonym 2 rock oil · · Synonym 3 fossil oil · · Synonym 4 oil · · Synonym 5 Characters · · e latin small letter e U+0065 l latin small letter l U+006C m latin small letter m U+006D o latin small letter o U+006F p latin small letter p U+0070 r latin small letter r U+0072 t latin small letter t U+0074 u latin small letter u U+0075