"I have the carrot."
Translation:Tá an cairéad agam.
cairéid is the plural "carrots":
tá cairéid agam - "I have carrots"
tá na cairéid agam - "I have the carrots"
cairéid is also the genitive singular, so cáca cairéid is "carrot cake" ("cake of carrot") and blas an chairéid is "the taste of the carrot".
cairéad is masculine, so it would only be lenited after a possessive pronoun - do chairéad.