1. A symbolic language that uses shared conventions to compress ideas, relations, or structures into reusable units that can participate in further expressions, operations, or relationships.
The meaning of a Yaku is resolved within a context or field: the same symbol
may mean different things in different contexts, as long as the relevant convention makes the meaning clear.
2. A symbol, term, or locally defined expression used in that language. A Yaku
may be widely shared, such as =, ∑, or ∈, or created locally for a particular problem, document, or community.
Think of established Yaku as shared libraries and locally defined Yaku as macros. Mathematics is one of the largest and oldest ecosystems built from Yaku, but Yaku can also appear in
physics, programming,
music, diagrams, and other systems of structured expression.
Short for the
Japanese 約語 (yakugo). 約 (yaku) carries meanings related to binding, agreement, summarizing, and compression.
“E = mc² is tiny, but it activates a
huge shared
library of meaning. That’s Yaku.”
“No standard symbol for this yet. I’ll
define my own Yaku.”
“Without knowing the field, you can’t tell what m means. Yaku gets its meaning from the convention it is connected to.”