Top Definition
The phrase used to judge how sexually aroused you were, or how sexually aroused someone would make you.
The phrase plays on 0 - 60mph, with "Semi" being a half erect penis.
*DAMN! I went 0 to semi in 2.4!

*She'd get it 0 to semi in about 1.7!
by DaveG217 May 20, 2006
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