What’s the difference between practical and practicable? There’s a practical distinction, and I hope you will find my explanation practicable.
The words both stem ultimately from the Greek term praktikos, meaning “practical.” However, while practical refers to something that is effective, useful, or easy to use, practicable means “something that is or could be done.” A practical idea is one that is sensible because it can be implemented, and a practical can opener, for example, is one designed to be easy to use. (The antonyms are impractical and impracticable.)
The definition of practical is even more precise in the performing arts: A practical chair, for example, is one that is actually used in the course of the performance; a nonpractical chair is used as a set decoration but may not be functional. (For example, though it looks nice, it may be made of fragile materials and may not be strong enough for anyone to actually sit on.) Practical also shows up in the phrase “practical joke,” which derives from the rare sense of the verb practice that means “deceiving, or taking advantage of, someone.”
Besides the verb form of practice, which means “rehearse or prepare, or to apply, or to habitually do something,” as well as “undertake professional work in” (as in the phrases “practice medicine” and “practice law”), and the noun equivalent, there are several other words stemming from the same Greek term.
Practic, for example, is a rare adjectival and noun form meaning, respectively, “practical” and “practice,” and praxis refers to engaging in an art, science, or skill or to customary conduct, or to practical application of a theory. A practicum is a course of study in which clinicians or educators are supervised in practicing what they have already learned in theory.
The adjective practiced means “expert,” and the adjective practicing has ordinary connotations related to the definitions of practice above but also applies to adhering to the customs of a religion. Malpractice, meanwhile, in medicine refers to improper care and in law applies to abusing a position of trust.