Definition
Hence is a compact, formal way of saying 'for this reason, it follows that'. It draws a line from a cause you have just stated to the conclusion that flows out of it, which is why it likes to sit between a fact and its consequence. Older, more literal senses survive too — 'a week hence' means a week from now, 'get hence' means away from here — but in academic prose it is almost always the logical 'therefore'. Unlike 'because', it points forward to the result rather than back to the cause.
Examples
- The samples were contaminated; hence, the results cannot be trusted.
- The bridge was built in 1890 and hence predates every other structure in the survey.
- The readings rose only at dawn; hence we can infer that sunlight drives the reaction, and the original hypothesis still holds.
Collocations
hence the name·hence the need for·a few years hence·hence it follows that·hence the delay
Synonyms
therefore·thus·consequently·accordingly·so
Word family
henceforth (adverb)·henceforward (adverb)
In TOEFL & IELTS
A clean, formal connector that lifts Writing above 'so'. Two patterns: as a sentence adverb with a comma ('…contaminated; hence, the results…'), or fronting a verbless noun phrase ('hence the delay', 'hence the need for caution'). Don't follow it with 'that'. Use it sparingly — one or two per essay reads as control, more reads as a tic.