selci -sle- gismu

x1 is a cell/atom/unit/molecule of x2; x1 is an indivisible, most basic subunit of x2.

(x2 generally has mass nature); (cf. kantu for properties, activities; ratni, gradu)

In notes:

gradu
x1 [magnitude] is a unit/degree of/on scale/reference standard x2 (si'o) measuring property x3.
kantu
x1 is a quantum/ray/elementary particle/smallest measurable increment of property/activity x2.
ratni
x1 is an atom of element/atomic number x2 of isotope number/atomic weight x3.
gugypausle
s1 is a county/district/province (second-level administrative division) of country s2=g1.
jempausle
x1 is an army brigade/regiment, a subdivision of army unit x2 which serves country/nation/group x3.
kinsle
x1=s1 is a frame from motion picture x2=k1 about x3=k2 [plot/theme/subject/activity]
mivysle
x1 is a biological cell of x2.
mulna'usle
s1=mn1 is an indivisible / prime number in integer domain s2.
slemidju
x1 is a nucleus of cell x2 [default biological].
songripausle
x1 is an army platoon, a subdivision of army unit x2 which serves country/nation/group x3.
trupausle
s1 is a sub-division of the Ministry/Department of t2.
xumsle
s1 is a molecule of chemical x2.