I. noun 1. an expression designed to call something to mind without mentioning it explicitly; an indirect or passing reference • an allusion to Shakespeare
• a classical allusion.
2. [ mass noun] — the practice of making allusions. • the use of allusion.
– origin mid 16th cent. (denoting a pun, metaphor, or parable): from French, or from late Latin allusio(n-), from the verb alludere (see allude).