ralju -ral- gismu

x1 is principal/chief/leader/main/[staple], most significant among x2 (set) in property x3 (ka).

Staple (= ralselpra); general/admiral/president/principal leader (= ralja'a, ralterbe'e; use additional terms to distinguish among these); also primary, prime, (adverb:) chiefly, principally, mainly; (x2 is complete specification of set). See also vajni, te bende, minde, lidne, jatna, jitro, gidva, midju.


In notes:

bende
x1 is a crew/team/gang/squad/band of persons x2 directed/led by x3 organized for purpose x4.
gidva
x1 (person/object/event) guides/conducts/pilots/leads x2 (active participants) in/at x3 (event).
jatna
x1 is captain/commander/leader/in-charge/boss of vehicle/domain x2.
jitro
x1 has control over/harnesses/manages/directs/conducts x2 in x3 (activity/event/performance).
lidne
x1 precedes/leads x2 in sequence x3; x1 is former/preceding/previous; x2 is latter/following.
midju
x1 is in/at the middle/center/midpoint/[is a focus] of x2; (adjective:) x1 is central.
minde
x1 issues commands/orders to x2 for result x3 (event/state) to happen; x3 is commanded to occur.
vajni
x1 (object/event) is important/significant to x2 (person/event) in aspect/for reason x3 (nu/ka).
ra'u
discursive: chiefly - equally - incidentally.
kagytruralju
r1 is CEO (Chief Executive Officer)/MD (Managing Director) of company/corporation/firm t2=k1.
raldargu
x1 is a highway to x2 from x3 with route x4
raltca
x1 is a/the capital of x2.
raltu'a
x1 is the mainland of x2
ralxelbo'a
r1 is the frequency of the carrier wave of signal b1.
truralju
r1 is the head-of-government of polity t2.
protagonista
x1 is a/the protagonist/main character/primary personal figure in narrative/story/enterprise x2