Particular with reference to a related universal proposition. (Merriam – Webster)
A person holding a subordinate position. (Merriam – Webster)
A particular proposition that follows immediately from a universal. (Merriam – Webster)
An army officer whose rank is lower than captain. (Cambridge Dictionary)
An officer in the British army below the rank of captain, especially a second lieutenant. (Oxford Dictionaries)
Of lower status. (Oxford Dictionaries)
Lower in rank; subordinate. (Dictionary.com)
A subaltern is an officer of middle rank in the British army. (Collins Dictionary)
The Subaltern Officer. — A Narrative.
Can the Subaltern Speak? Gayatri Spivak and Post-Colonialism.