noun
diagonal cross; X-shaped cross
Refers to an X-shaped crossing or arrangement, such as crossed lines, beams, or a diagonal intersection.
柱にぶっ違いの筋交いを入れて補強した。
We reinforced the pillar with diagonal cross braces.
この模様はぶっ違いの線でできている。
This pattern is made of X-shaped lines.
筋交い is a diagonal brace or strut, often used in construction, while ぶっ違い emphasizes the X-shaped crossing itself.
The word is a compound of ぶっ (an emphatic prefix derived from 打ち) and 違い (difference, crossing). The exact historical derivation is uncertain, but it describes an X-shaped crossing.