downthrowPronunciation: /ˈdaʊnθrəʊ/ GeologyDefinition of downthrow verb (past downthrew; past participle downthrown) [with object] displace (a rock formation) downwards: in the downthrown areas the carbonates have escaped exposure noun a downward displacement of rock strata. downthrow in other Oxford dictionaries Definition of downthrow in the US English dictionary