straight-line
straight-line — collocation
1. going from one point to another without turning or bending on the way
going from one point to another without turning or bending on the way
Daniel drew a straight-line arrow from the station to the museum.
pattern: straight-line + arrow
The app showed a straight-line path across the school field.
pattern: straight-line + path
Zuri checked the straight-line distance before booking the boat ride.
The robot followed a straight-line track through the empty warehouse.
- direct
is broader and can describe a route without focusing on geometric shape
- point-to-point
often stresses travel between two fixed places in transport or mapping
- linear
sounds more technical and is common in math or design
文法句型
straight-line route
straight-line path
straight-line distance
用法筆記
Usually appears before nouns that describe movement, measurement, or shape. It stresses the direct route itself, not whether the trip is fast or easy.
常見錯誤
straight-line — adjective
1. used for movement, measurement, or shape that follows the shortest direct course
used for movement, measurement, or shape that follows the shortest direct course
The survey uses straight-line distance, not road distance, between villages.
collocation: straight-line distance
Wei measured the straight-line gap from the tower to the harbor.
The game rewards the car with the highest straight-line speed.
Engineers compared the straight-line length with the older curved route.
- direct
is the everyday choice and is less geometric
- linear
is more technical and often used in science or design
- point-to-point
is common when the start and end places are the main focus
文法句型
straight-line distance
straight-line speed
straight-line measurement
用法筆記
Most often modifies nouns such as distance, speed, path, or measurement. Use it when the direct course matters more than real roads or obstacles.
常見錯誤
2. describing an engine whose main working parts are set in a single row
describing an engine whose main working parts are set in a single row
Gabriel bought a used car with a straight-line six engine.
collocation: straight-line six engine
The museum label explains how a straight-line engine keeps its cylinders together.
Our teacher drew a straight-line four engine on the board.
The old taxi used a straight-line engine with every cylinder in one row.
文法句型
straight-line engine
straight-line six
straight-line four
用法筆記
This sense is mainly used in car and engine talk. It contrasts with V-shaped or flat engine layouts, so it usually appears before engine, four, or six.
常見錯誤
3. describing a mechanism built to create or copy motion that travels forward in on
describing a mechanism built to create or copy motion that travels forward in one direct line
The workshop tested a straight-line linkage on the new cutting machine.
collocation: straight-line linkage
Engineers chose a straight-line mechanism to move the blade evenly.
pattern: straight-line mechanism
The model uses a straight-line guide so the drill head travels directly.
Rafael watched the straight-line device copy the pen's motion across the sheet.
- linear-motion
is close in engineering writing but often appears in longer compounds
- rectilinear
is more formal and mathematical than straight-line
- rotary
describes motion that turns around a center
- curved-path
describes motion that bends instead of staying direct
文法句型
straight-line linkage
straight-line mechanism
straight-line device
用法筆記
Use this sense in mechanical design, where the key idea is producing a true direct motion from another movement. It is narrower than the engine-layout sense in adjective/2.
常見錯誤
4. describing a plan where the amount paid or charged stays the same in each period
describing a plan where the amount paid or charged stays the same in each period
The bank offered a straight-line repayment plan for the shop loan.
collocation: straight-line repayment plan
With straight-line payments, Linh paid the same amount every month.
pattern: straight-line payments
The finance sheet compares straight-line charges with rising-rate ones.
Our lease uses a straight-line charge over the full three-year term.
- level-payment
is common in finance when each payment stays equal
- even
is a broader everyday word and is less technical
文法句型
straight-line repayment
straight-line charge
straight-line plan
用法筆記
This sense belongs to accounting and lending language. It highlights that each payment period carries the same amount, unlike plans where early and later payments differ.