The noun 壁 (bì) means "wall" or "cliff face." It typically refers to a steep, vertical surface such as a rock wall or the side of a mountain. In classical poetry, 题壁 means "to inscribe on a wall," a common practice for poets leaving verses at scenic sites.
攀岩的时候他紧紧抓住了岩壁。
Pānyán de shíhou tā jǐnjǐn zhuā zhù le yánbì.
While rock climbing, he held tightly onto the rock wall.
古代诗人喜欢在寺庙的墙壁上题诗。
Gǔdài shīrén xǐhuān zài sìmiào de qiángbì shàng tí shī.
Ancient poets liked to inscribe poems on the walls of temples.
这面壁上刻着很多古老的文字。
Zhè miàn bì shàng kè zhe hěn duō gǔlǎo de wénzì.
Many ancient characters are carved on this wall.