noun
wooden wedding anniversary; 5th wedding anniversary
Refers specifically to the 5th wedding anniversary, following the traditional naming convention for anniversaries.
今年は木婚式だから、木でできたプレゼントを贈ろうと思う。
This year is our wooden wedding anniversary, so I'm thinking of giving a gift made of wood.
Compound of 木 (wood) + 婚 (marriage) + 式 (ceremony), following the Western tradition of naming wedding anniversaries after materials.