The word sent is not a noun; the word sent is the past participle, past tense of the verb to 'send'. The past participle is also an adjective (past tense).
The noun forms for the verb to send are sender, and the gerund, sending.
The word 'apology' is a noun, a singular, common, abstract noun; a word for an expression of regret; a word for a poor substitute. example: He sent an apology for missing the meeting.
common noun
Common
Common noun
common
Pea is a common noun, and peas is the plural...still a common noun.
A common noun.
Most definitely a common noun.
No it is not
Camel is a common noun.
Th word tail is a common noun because the first letter of a proper noun is capitalized.
common