A columbarium is a place for the respectful and usually public storage of cinerary urns, a vault with niches for urns containing the ashes of cremated bodies. The term comes from the Latin columba (dove, dovecote) and originally referred to compartmentalized housing for doves and pigeons. The word columba comes from the Greek word colymbis [wild ducks or wild birds that use to dive into the see water; Gr.: κολυμβίς] from the verb colymbo (to dive, duck; Gr.: κολυμπώ).
From the same root:
Columbus [From the Greek Colymbos (diver), Gr.: κόλυμβος], Columbia, Colombia etc.
In modern Greek (Romeika)
a) colymbo: swim, bath [Gr.: κολυμπώ ]
b) colymbi (or colymbisi): swimming [Gr.: κολύμπι or κολύμβηση]
c) colymbitirio: swimming-pool, lido [Gr.: κολυμβυτήριο]
d) colymbitis: swimmer [Gr.: κολυμβητής]
e) colymbithra: font [Gr.: κολυμβήθρα]
Saint Columba was a sixth-century Orthodox Irish saint, who founded an important monastery on the Scottish island of Iona.
In the early centuries of Christianity the name Columba was popular, because the "dove" is a Cristian symbol for the Holy Spirit and peace.
See more at: http://stcolumbamonastery.org/about/our-patron/