- a floating colony of hydrozoans of the genus Velella, having a vertical crest that is used as a sail.
Origin of velella
1825–35; < New Latin, equivalent to Latin vēl(um) sail + -ella -ella
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for velella
A Velella also was caught in the open bay: this is the first which has been observed in so high a latitude.
As the barnacles grew larger, the remains of the velella changed into large excrescences, half the size of a walnut.
I kept one specimen, to show old and young barnacles attached to the same Velella.
Thus in Velella free medusae are produced, which have been described as an independent genus of medusae, Chrysomitra.