[ teerst ]
/ tɪərst /
(of an escutcheon) divided vertically or horizontally into three equal parts.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for tierced
Tierced in pale (divided into three equal divisions by two vertical lines), a form seldom met with in English Heraldry.The Handbook to English Heraldry|Charles Boutell