(physics) The only stable isotope of aluminium, ²⁷₁₃Al, having thirteen protons and fourteen neutrons

The group of famous musicians who have died at age 27.

(physics) A doubly magic isotope of hassium - ²⁷⁰₁₀₈Hs; it is the longest-lived one known, having a half-life of several seconds.

Abbreviation of twenty-seventh.