IPA: /ˈrɛərər/
KK: /ˈrɛrər/
Less common or unusual than something else.
This species of bird is rarer than the others in the region.
Rarer → It is formed from "rare" (from Latin *rarus*, meaning uncommon or infrequent) and the comparative suffix "-er" (meaning more). The word "rarer" means more uncommon or less frequent than something else.
Think of something that is 'uncommon' ('rare') and when you add '-er', it means it is 'more uncommon'. This helps you remember that 'rarer' refers to something that is less frequently found.