“Cut one’s teeth” is an idiom meaning to gain initial experience or form one’s basic skills in a particular activity or profession.

When someone “cuts their teeth” on something, they go through early, often formative, hands‑on practice that shapes their later abilities and career. The phrase evokes the image of a young person’s first, sometimes awkward, attempts — like a baby’s first teeth coming in — and is commonly used to highlight the value of learning by doing.

Usage usually follows patterns such as “cut one’s teeth on” or “cut his/her teeth in”: for example, “She cut her teeth on community theater before moving to Broadway” or “He cut his teeth in sales.”

It often implies a period of apprenticeship, modest beginnings, or tackling practical challenges that build competence and confidence.

The tone is neutral to conversational and fits well in both journalistic and everyday contexts. Synonyms include "get one’s start," "learn the ropes," or "gain hands‑on experience." Unlike simply learning theory, cutting one’s teeth suggests exposure to real situations — mistakes, problem solving, and growth.