Real Dictionary

rare
You use rare to emphasize an extremely good or remarkable quality.
adjective: An event or situation that is rare does not occur very often.
adjective: Meat that is rare is cooked very lightly so that the inside is still red.
adjective: Something that is rare is not common and is therefore interesting or valuable.

rare in American English 1
not frequently encountered; scarce; unusual
adjective: coming or occurring far apart in time; unusual; uncommon

rare in American English 2
not completely cooked; underdone; partly raw
adjective: cooked just slightly

rare in American English 3
rear2 (sense 5) rear2 (sense 6)
intransitive verb

rare in British English 1
adjective: not widely known; not frequently used or experienced; uncommon or unusual

rare in British English 2
adjective: (of meat, esp beef) very lightly cooked

rare in Hospitality
adjective: Meat that is rare is cooked very lightly so that the inside is still red and cold.