со́бственно
adverb
proper
со́бственно геоме́трия
geometry proper
со́бственно го́род
the city proper
as a matter of fact, in fact
used in the following idiomatic expressions
со́бственно говоря́
as a matter of fact, strictly / properly speaking
это, со́бственно, не совсе́м так
strictly / properly speaking it is not quite like that
э́тим, со́бственно, и объясня́ется...
this, in fact, explains ...