1. Relating to the seas, especially smaller or inland seas
   "deposits of sediment in gulfs and seas rather than in the ocean proper are known as thalassic deposits"

See also: sea

• at a loss
• at a low price
• at a lower place
• at a time
• at all
• at all costs
• at an equal rate
• at any cost
• at any expense
• at any rate
• at arm's length
• at bay
• at best
• at bottom
• at close range
• at fault
• at first
• at first blush
• at first glance
• at first hand
• at first sight
• at hand
• at heart
• at home
• at issue