2 letters

Tn

3 letters

btn ctn stn mtn

4 letters

altn extn attn CStn pptn detn lctn jctn

5 letters

syftn iortn destn distn thatn

6 letters

pufftn

14 letters

Thingvallavatn

Words with a ∙ are valid Scrabble words (SOWPODS word list)