Tchèque tvrdy -LRB- '' hard '' -RRB-, polonais twardy -LRB- '' hard '' -RRB-, Russian -LRB- '' hard '' -RRB- -RRB-, from Old Church Slavonic -LRB- '' firm '' -RRB-, from Proto-Slavic \ * tv rd.
Tchèque tvrdy -LRB- '' hard '' -RRB-, polonais twardy -LRB- '' hard '' -RRB-, Russian -LRB- '' hard '' -RRB- -RRB-, from Old Church Slavonic -LRB- '' firm '' -RRB-, and from Proto-Slavic \ * tv rd.