cool tankard
/ˌkuːl ˈtaŋkəd/noun
1A cooling drink, typically made of wine and water, and flavoured with lemon juice, spices, and borage. Now historical.
2Originally English regional. The herb borage, Borago officinalis.
Origin
Late 17th century; earliest use found in Thomas Brown (bap. 1663, d. 1704), writer. From cool + tankard.