sinxa -sni- gismu

x1 is a sign/symbol/signal representing/referring/signifying/meaning x2 to observer x3.

Also: x1 signifies x2; (adjective:) x1 is significant/meaningful/of import; signal an action (= sniti'i), connotation (= se sibyti'isni, sibyti'ismu). See also lerfu, tcita, barna, mifra, smuni.

In notes:

barna
x1(s) is a/are mark(s)/spot(s) on x2 of material x3.
lerfu
x1 (la'e zo BY/word-bu) is a letter/digit/symbol in alphabet/character-set x2 representing x3.
mifra
x1 is encoded/cipher text of plain-text x2 by code/coding system x3; x1 is in code; x3 is a code.
smuni
x1 is a meaning/interpretation of x2 recognized/seen/accepted by x3.
tcita
x1 is a label/tag of x2 showing information x3.
ceisni
x1=s1 is an idol/a sign/symbol representing god/demon/property x2=s2 to observer x3=s3
jecysni
x1=s1 is the national symbol representing country/state/polity x2=s2=j1 to observer x3=s3
nalra'a
x1 is irrelevant/unrelated to x2; x1 is arbitrary in relation to x2 [object of comparison; context or referent].
selsni
x1 is the meaning of symbol x2 as observed by x3
smuvanbi
v1 is the context of meaning v2=s1 of event/action/object s2 recognized by s3.
snicmaci
c1 is an algebra of type/describing c2
snicne
x1 is a variable taking value x2 under conditions x3.
snigau
x1 assigns symbol/variable x2 to value/referent x3 for observer x4.
snisku
x1 expresses/transmits symbol/meaningful expression x2 for audience x3 by doing x4 (ternary relation between x1, x2 and x3)
tapsni
si1 is a track of st1 treading on surface st2 using limb st3
zgika'usni
s1 is a music note (symbol).
metfo
x1 (bridi) is a metaphor/figurative expression having literal meaning x2 to observer x3
vinpa
x1 is a deliberately placed sign meaning x2 to x3 (x2 being relevant to x3's situation when perceiving x1)
te'i (exp!)
at a point on time axis
almapamla
x1 is a plant symbolizing the idea of love, to x2.
ambigu'o
x1 is ambiguous, open to interpretations x2 (plural of property of x1)
blazone
x1 (object, text) is a blazon, verbal or written description of the coat of arms x2
esku
x1 is the text for x2 (concept) according to x3 in language x4; x1 is how x3 would word x2 in language x4; x3 would say x1 when they would want to communicate x2 in language x4; x1 is text(ual) / a quote (meaningful) in language x4.
rinsita
x1 is a heart symbol / is heart-shaped ( ♥ )
slogane
x1 (text, entity) is a slogan of x2 (entity)
snitatu
x1 is a tattoo
uensni
x1 is text meaning x2 in language x3