IPA: /ˈstreɪtə/
KK: /ˈstreɪtər/
More direct or less curved than something else.
The new road is straighter than the old one, making it easier to drive.
A type of cigarette that contains tobacco and is not mixed with other substances like marijuana.
He prefers to smoke straighter instead of blunts.
Straighten is formed from "straight" (from Old English *streht*, meaning not bent or curved) and "-en" (a suffix used to form verbs). The word "straighter" is the comparative form of "straight," meaning more not bent or more direct.
Think of something that is 'not bent' ('straight') and how 'straighter' means it is more so — like a line that is becoming more direct.