The spelling of the word "back gray" can be explained using IPA phonetic transcription. The first syllable "back" is pronounced as /bæk/ with a short sound of the "a" vowel. The second syllable "gray" is pronounced as /ɡreɪ/ with a long sound of the "a" vowel. The "e" in "gray" is pronounced as a schwa sound /ə/. Together, the word is pronounced as "bak grey." It is commonly used to describe a shade of gray that has a blue or green undertone.