New_York_Lower_East_Side_Tenement_Museum’s_landmark_tenement_building_at_97_Orchard_Street Photo from Wikicommons.

While the abbreviation and the “fix” (look the word up or use “spellcheck”) seem obvious, if this is a comment you get often on your papers, consider reviewing available lists of commonly misspelled words and “homophones” and “homonyms,” words that sound alike but are spelled differently, such as “their,” “they’re,” and “there” or edition vs. addition.