first-degree \ˈ ̷ ̷ ̷ ̷| ̷ ̷\adjective Etymology: from first degree (as in such phrases as of the first degree, to the first degree) 1.: of the lowest or mildest in a series < first-degree initiation > < first-degree laceration > 2.: of the highest or most serious in a series < first-degree murder >