IPA: /ˈlaɪtɪst/
KK: /ˈlaɪtɪst/
The smallest amount of weight or the least heavy compared to others.
This is the lightest backpack I have ever owned.
Comparative: lighter
Superlative: lightest
Lightest → It is formed from "light" (from Old English *leoht*, meaning not heavy) and the suffix "-est" (meaning the most). The word "lightest" means the most not heavy or the least weighty.
Think of something that is 'not heavy' ('light') and remember that 'lightest' means the most not heavy.