Ela, somethign similar here with South Slavic words:) In Russia Church Slavonic languge was used in Church books and up to 18th cnetury it was often the basis of Russian literacy. So we have two forms for certain words. E.g.
gorod, grad "city".
The former is the normal word for a city. The later is 'elevated' form, with an epic ring to it, met in classic poetry but well familiar to us. E.g. novel Град обреченный (doomed city) by Strugatsky brothers: this 'grad' and inversion of adjective, and Slavonic pronunciation of 'обрече́нный' (instead of 'обречённый') makes it sound as if it was from the Bible!
Indo-Euroepan /tort/ and /tolt/ (/t/ for a random consonant) famously gave -ra-/-la- in South Slavic and -oro-/-olo- in East Slavic. So:
gorod - Russian (and 'ogorod', vegetable garden)
grad - South Slavic
garden, yard, Latin hortus.
In Serbia, of course 'grad' is just a normal word for 'city'. I'm not sure about Croatia, but I think too (just looked in Croatin wiktionary,. it has ruski: <a href="https://hr.wiktionary.org/wiki/%D0%B3%D0%BE%D1%80%D0%BE%D0%B4#
город_(ruski_jezik)" title="город">город</a> <sup><a href="https://ru.wiktionary.org/wiki/%D0%B3%D0%BE%D1%80%D0%BE%D0%B4
" class="extiw" title="ru:город">(ru)</a></sup>, <a href="https://hr.wiktionary.org/wiki/%D0%B3%D1%80%D0%B0%D0%B4#
град_(ruski_jezik)" title="град">град</a> <sup><a href="https://ru.wiktionary.org/wiki/%D0%B3%D1%80%D0%B0%D0%B4
" class="extiw" title="ru:град">(ru)</a></sup> m.
(starinski ili pjesnički)). Not exactly precise definition, not just archaic and songs. It also sounds soemwhat solemn.And for Russians it is a very distinctve feeling: sounds as if it wa some dialect of Russian, where elevated words are used so casually.