Definition of straight-line
1 : being a mechanical linkage or equivalent device designed to produce or copy motion in a straight line
2 : having the principal parts arranged in a straight line
3 : marked by a uniform spread and especially in equal segments over a given term
straight-line amortization straight-line depreciation
4 : occurring, measured, or made in or along a straight line
straight-line motion straight-line extrapolation
Keep scrolling for more
Keep scrolling for more
Test Your Vocabulary
Slippery Words Quiz—Changing with the Times
- What is an earlier meaning of nice?

Test your vocabulary with our 10-question quiz!
TAKE THE QUIZ
Spell words. Make bears.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridgedWords at Play
Ask the Editors
Word Games
Slippery Words Quiz—Changing with the Times
Do you know these earlier meanings of words?
Take the quizWords of Snow and Ice Quiz
A selection of words from the chillier parts of t...
Take the quizHow Strong Is Your Vocabulary?
Test your vocabulary with our 10-question quiz!
Take the quizPlay the game
Share straight-line
Time Traveler for straight-line
The first known use of straight-line was in 1843
See more words from the same year