Anchor
An anchor is a device, normally made of metal, used to connect a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin "ancora", which itself comes from the Greek ἄγκυρα ("ankura").
Anchor ice
Anchor ice may be formed in the shallow intertidal or subtidal during storms in cold weather, when the uppermost layers of the water column are churned up by strong winds or waves. This type of anchor ice can be found primarily in the Arctic, where submerged ice may be observed to completely cover the substrate to depths of up to 2m, with some anchor ice cover observed at more than 4.5m depth.