hawser, class (genus), rope, cord, cable
綱 centers on a strong, thick rope or cable that binds or leads. The biological class sense extends this idea to a major grouping that ties related organisms together.
綱 combines 糸 (thread) with 岡, which likely contributes the sound コウ. The character originally referred to a thick rope or hawser, and the biological class sense is a later semantic extension.
The left side 糸 is thread, and the right side 岡 looks like a sturdy frame. Picture thread woven into a thick, strong rope that can hold a heavy load.
For コウ, imagine a thick rope coiling around a post: the word 'coil' sounds like コウ, and the rope coils tightly.
yokozuna (highest rank in sumo); grand champion
rope; cord; line
lifeline; safety rope; safety tether
main principle; gist; general plan; guidelines; outline
reins; bridle
tug of war
tightrope walking; high-wire act; funambulism
general plan; main points; summary; platform (e.g. for a campaign); mission statement
fundamental principles; main lines
izuna; pipe fox; fox-like spirit kept inside a bamboo tube and used by its master to perform divinations and curses
least weasel (Mustela nivalis)
mooring rope
law and order; (official) discipline
mooring line; mooring rope; painter
Arachnida
Gnetopsida (class of gymnosperms)
Graptolithina (class of extinct hemichordates)
three bonds (in Confucianism: master and servant, father and son, husband and wife)
three monastic positions with management roles at a temple
superclass