semiformal

Somewhat formal.

The HLA defines the rules of interoperability, a semiformal methodology for specifying simulation and federation object classes, and the interface specification that is a precise specification of the functional actions that a simulation may invoke.

When wearing the dragon robe on semiformal occasions, a single necklace was appropriate. Only the empress or empress dowager could wear a main necklace formed of Manchurian pearls, the other two being made of coral.

Of clothing: having a level of formality between that of informal and formal wear.

Suits have largely replaced guayabera shirts as business and semiformal wear for middle and upper-class Panamanian men, made practical by the widespread use of air-conditioning in the cities.

Of an event: having a semiformal dress code.

The skirt was way too short, at least shorter than she preferred. It left exposed a good eight inches between her knee and thigh. But what choice did she really have? Casual cropped pants were hardly appropriate attire for a semiformal event.

A social event in which one is expected to dress in semiformal wear.

Bright-colored flyers decorated battered lockers, telling everyone to join the debate team, try out for the school play, and not to miss the fall semiformal this Friday. I wondered what a "semiformal" consisted of at a public school, not that I'd bothered to ask anyone.