1. (geomorphology) a conical mound with an ice core lasting more than a year; caused by permafrost uplift

Derived forms: pingos

Encyclopedia: Pingo

• Letter of Jeremiah
• letter of mark and reprisal
• letter of marque
• letter of the alphabet
• letter opener
• letter paper
• letter security
• letter stock
• letter telegram
• letter writer
• letter-perfect
• lettercard
• lettered
• letterer
• letterhead
• lettering
• letterman
• letterpress
• letters
• letters of administration
• letters of marque
• letters patent
• letters testamentary
• letterset printing
• letting