Radicals ( Radical13) two strokes in Kanji;

dimensional, e.g.

Nippon Syllabary 's one of the characters: su in Hiragana a.k.a. su in Katakana;

directional, e.g.

;

logical, e.g.

enter;
insert;

numerological, e.g.

2;

structural, e.g.

;

Radicals;