noun

• The act of applying or laying on, in a literal sense
• The substance applied.
• The act of applying as a means; the employment of means to accomplish an end; specific use.
• The act of directing or referring something to a particular case, to discover or illustrate agreement or disagreement, fitness, or correspondence.
• (computing) A computer program or the set of software that the end user perceives as a single entity as a tool for a well-defined purpose. (Also called: application program; application software.)
• A verbal or written request for assistance or employment or admission to a school, course or similar.
• (bureaucracy, law) A petition, entreaty, or other request, with the adposition for denoting the subject matter.
• The act of requesting, claiming, or petitioning something.
• Diligence; close thought or attention.
• A kind of needlework; appliqué.
• (computing theory) The substitution of a specific value for the parameter in the abstraction, in lambda calculus.
• (obsolete) Compliance.