Arrēn (also arsēn) means male — the biological designation of maleness, as opposed to thēlys (female). Appearing about 9 times in the NT, it emphasizes sexual distinction as a created biological reality. It differs from anēr (a man as a husband or adult male) and anthrōpos (a human person). Arrēn focuses on the basic category of maleness.
Paul's use of arsēn in Romans 1:26–27 and 1 Corinthians 6:9 grounds sexual ethics in created order. In Romans 1, the exchange of natural relations between thēlys (female) and arsēn (male) is presented as a symptom of theological inversion — the rejection of the Creator reflected in the confusion of His creation. Galatians 3:28 uses arsēn in its counterpoint: "There is neither male nor female" in Christ — not erasing biological distinction but declaring equal dignity and access to grace. The arsēn firstborn being dedicated to God (Luke 2:23, citing Exodus 13:2) connects Jesus to the Passover deliverance.