threshold
A threshold is the strip of wood under a doorway — and, ever since, every point where one state ends and another begins. Science speaks of the threshold of hearing, the pain threshold, the threshold dose below which nothing happens; politics of electoral thresholds; life of being on the threshold of adulthood. Below the line, nothing; at the line, hesitation; past it, a different world. The crossing takes a step. Reaching the line can take years.
- on the threshold of
- reach a threshold
- the pain threshold
- below the threshold
- a threshold effect
=limit, boundary, starting point, brink, verge
TOEFL science passages use it constantly — sensory thresholds in psychology, temperature thresholds in ecology, threshold effects in economics. 'On the threshold of' is the figurative collocation IELTS rewards. Pronunciation trap: it is THRESH-hold, with one 'h' sound carrying both syllables.