lord, chief, master, main thing, principal
主 centers on the central or controlling figure: a lord, chief, or master, and by extension the main or principal thing.
主 originally depicted a lamp or torch with a flame above a stand, symbolizing the master of the house or the central figure. The modern form retains the dot above 王, though the historical connection to a lamp is not obvious from the current shape.
The dot above 王 looks like a crown or mark of authority over a king, making this the lord or master.
For シュ, imagine a shoe placed on the master's throne: shoe -> シュ, and the master sits above all.
(one's) master; (one's) employer; (one's) lord
head (of a household); proprietor (of a store); proprietress; landlord; landlady; master (of a servant)
chief; main; principal; important
head (of a household, etc.); leader; master
doctrine; rule; principle; -ism
claim; insistence; assertion; advocacy; emphasis; contention; opinion; tenet
protagonist; main character; hero; heroine
democracy; popular sovereignty
sponsorship (i.e. conducting under one's auspices); promotion; organizing; organising; hosting; staging
Democratic Party
head (of a household); proprietor (of a store); proprietress; landlord; landlady
starring (in a film, play, etc.); playing the leading part
chief; main; principal; major
independence; autonomy; self-reliance
housewife; mistress (of the house); homemaker
owner; proprietor; possessor (e.g. of talent, beauty, etc.)
main constituent; core; nucleus
leading part; leading actor; leading actress
(the) mainstream
shareholder; stockholder
leadership; initiative; spearhead
(pet) owner; keeper
Buddhist priest; bonze
person in charge; senior staff; manager; chief; head
shopkeeper; storekeeper; proprietor of a shop
main force; main strength
subjectivity; subject (philosophical); ego
sovereignty; supremacy; dominion
monarch; sovereign; ruler; liege (lord)
saviour; savior; messiah
chairmanship; presidency; management
subject; theme; motif
staple food
head; chief
lord of a castle
doctor chiefly responsible for a patient's care; doctor in charge (of a patient); attending physician
commander-in-chief; supreme commander
landowner; landlord; landlady
subject
feudal lord; daimyo
main spindle; main shaft
mainly; primarily; mostly; largely; chiefly
main battery; main armament
mainly; chiefly; primarily; for the most part
landlord; landlady
principal offence; principal offense; principal offender
main; principal; chief; primary; major
household head; master; host (e.g. of a tea gathering); innkeeper; owner (e.g. of a hotel)
chief editor; managing editor
owner of a horse (esp. racehorse)
Shinto priest
main purpose; chief aim; focus
chief umpire; referee (soccer, boxing, etc.)
advocacy of war
employer
Marxism
leader (of an alliance); leading power
primary cause; main factor
supervision; management; supervisor; manager
Democratic People's Republic of Korea (North Korea); DPRK
paymaster; accountant
chief examiner or investigator
chief mourner
shipowner
editor-in-chief
advocacy; promotion
your husband; her husband
independent; responsible; active; proactive
hegemony; leadership; initiative
(Japanese) Tax Bureau
advocate (of a theory or principle); ideologist; ideologue
subjective
budget bureau
humanism; humanitarianism
totalitarianism
communism
egoism; egotism; selfishness
feudalism
imperialism
exclusivism; exclusionism
democracy
democratic state
democratic
nationalism
socialism
independent; autonomous; voluntary; of one's own initiative
liberalism
capitalism
sender (of a present)
militarism