Brennan \b-rennan, br(en)-nan\ as a girl's name (also used as boy's name Brennan), is of Irish and Gaelic origin, and the meaning of Brennan is "descendant of Braon?". Transferred use of the surname. Braon?is a personal name meaning "moisture, drop" or may also be a contracted form of Brendan.

For more information, see also the related name Brenna.

Baby names that sound like Brennan are Brynnan and Brenyn. Other similar baby names are Brennah, Breanna, Breonna, Breona, Breina, Breean, Breann, Breana, Breehan, Breena, Brenda, Brenndah, Brennda, Brenn, Brendah, Brynna, Brinna, Brenne and Brienna.