A military rank for a field officer above that of colonel and below the general ranks or flag ranks(noun)
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Use "senior colonel" in a sentence
"Colston's brigade entered the fight under its senior colonel and emerged under its fifth-ranking officer, a lieutenant colonel."
"Ewell's division: Maimed Dick Ewell, corps commander; Lawton, transferred; senior colonel Marcellus Douglass, dead; Trimble, twice wounded, promoted, now a prisoner; Early, a major general; Harry Hays, at his usual post."
"The only other senior colonel who could be advanced to fill a vacancy was Goode Bryan of the 16th Georgia."