From
http://www.ancestry.com/learn/facts/Fact.aspx?fid=10&ln=Seabright:
SeabrightEnglish: from a medieval continuation of an Old English personal name,
Sæbeorht, composed of the elements
sæ ‘sea’ +
beorht ‘bright’. The Middle English name was probably reinforced by the more common Old English name
Sigebeorht, whose first element is
sige ‘victory’.
Therefore, Seabright literally means ‘sea bright’.