梯子 (tī zi) is a common noun meaning 'ladder' — a portable structure with horizontal rungs or steps, used to climb up or down to otherwise inaccessible heights. The first character, 梯 (tī), specifically denotes a ladder or staircase and carries the core semantic meaning; the second character, 子 (zi), is a neutral diminutive suffix often attached to nouns in spoken Mandarin, adding no independent meaning but making the word sound more natural and colloquial.

This word refers to both household ladders (e.g., aluminum or wooden step ladders) and fixed structures like fire-escape ladders or library step stools. It appears frequently in instructions, safety warnings, home improvement contexts, and everyday descriptions of reaching high places — such as changing a lightbulb, painting a wall, or retrieving items from a high shelf. While 梯 alone can appear in compound words (e.g., 楼梯 lóu tī 'staircase'), 梯子 is the standard, standalone term for a freestanding ladder.