U+27D8 "⟘" Large Up Tack Unicode Character

U+27D8 "⟘" Large Up Tack is a mathematical and technical symbol representing a logical or semantic relation in formal languages, primarily defined as the negation of a down tack, often used in order theory or lattice theory to denote the concept of "does not meet" or a failure of a lower bound relationship. It visually resembles an inverted uppercase 'T' with a wider horizontal bar, and it belongs to the Miscellaneous Mathematical Symbols-A block, where it serves as a complementary operator to the similarly sized down tack, typically within contexts such as natural deduction or algebraic structures where precise relational negation is required.