Given an operad O (say, a symmetric sequence in a symmetric monoidal ∞-category C), an algebra over an operad, or O-algebra for short, is, roughly, a left module over O with multiplications parametrized by O.
If O is a topological operad, then one can say an algebra over an operad is an O-monoid object in C. If C is symmetric monoidal, this recovers the usual definition.
Let C be symmetric monoidal ∞-category with monoidal structure distributive over colimits. If f : O → O ′ {\displaystyle f:O\to O'} is a map of operads and, moreover, if f is a homotopy equivalence, then the ∞-category of algebras over O in C is equivalent to the ∞-category of algebras over O' in C.1
Francis, Proposition 2.9. - Francis, John. "Derived Algebraic Geometry Over E n {\displaystyle {\mathcal {E}}_{n}} -Rings" (PDF). http://www.math.northwestern.edu/~jnkf/writ/thezrev.pdf ↩