Definition
A wing design that is supported partly by its own internal structure and partly by external bracing, typically one or more struts running from the fuselage to the underside of the wing.
Plain English
A wing that is mostly self-supporting but still uses an external strut or two to help carry the load.
Context Anchor
Seen in discussions of wing construction and during preflight inspection of airplanes that have wing struts or other outside wing supports.
Derivation
From 'semi-' (Latin, meaning 'half' or 'partly') and 'cantilever' (an English engineering term for a beam supported only at one end). A cantilever wing has no external bracing; a semi-cantilever wing is partly cantilevered, with struts picking up the rest of the load.
Why Pilots Care
Knowing the wing is semi-cantilever explains why preflight inspection includes checking the wing struts and their attachment points -- those struts are carrying real structural load, not decoration.
Intuition Check
Semi-cantilever does not mean the wing is weak or only “half built.” It means the wing carries some load internally and shares some load with outside supports.
Example Sentence 1
The Cessna 172 has a semi-cantilever wing, with a single strut on each side bracing it to the lower fuselage.
Example Sentence 2
Early designs often featured semi-cantilever wings before manufacturers shifted to fully cantilevered structures.