means A journey from one place to another and back, especially a short one — or, as a verb, to stumble by catching your foot, or to set off a mechanism.

from From the Old French 'triper,' to hop, leap, or strike with the foot — the same skipping-dance energy you hear in 'trippingly.' For centuries 'trip' meant a light, nimble step, which is why you can still 'trip the light fantastic.' The 'stumble' sense grew from the foot-striking idea (a misjudged step), and only later — possibly by the 14th–15th centuries — did 'trip' come to mean a short voyage, the kind of quick, light passage a nimble traveller might make. The 'psychedelic experience' sense is a much newer slang twist from the mid-20th century.