The word բարդ (part) is an interesting term that, despite how it sounds for a Western Armenian speaker, has nothing to do with part. (In Classical and Eastern Armenian, it is pronounced bard.)
We do not know for sure what the origin of the word is. The oldest meaning attested, “pile, heap” (as in a heap of wheat or a pile of papers), is in the fifth century A.D. translation of the Bible. Later on, the verb partel (բարդել “to pile”) appeared too. It seems that the idea of items gathered together brought forward the specific meaning “compound (word)” that appeared in the histories transmitted under the names of Agatangeghos and Pavstos Buzand, also written in the fifth century. Later on, a kind of flower that flourished at the beginning of the spring was also named part.
The original meaning “pile, heap,” although still appears in contemporary dictionaries, seems to have lost much of its use.
Today, we have the following meanings related to part in Modern Armenian:
բարդ (part) “complicated”: Բարդ անձնաւորութիւն մը (part antznavorootioon muh “a complicated personality”)
բարդ (part) “complex”: Բարդ մեքենայ մը (part mekena muh “a complex machine”)
բարդ (բառ) (part parr) : “compound (word)” (for instance, օդանաւ/otanav “airplane” is a part parr)
բարդ (part) “battery”: Ելեկտրական բարդ (yelegdragan part “electrical battery”)
We also have some derivative words, such as:
բարդացնել (partatsunel) “to complicate”: Խնդիրը բարդացաւ (khuntiruh partatsav “the issue became complicated”)
բարդել (partel) “to pile”: Թուղթերը բարդեց (tooghteruh partets “s/he piled the papers”)
բարդութիւն (partootioon) “complication”: Բարդութիւններ եղան (partootioonner yeghan “there were complications”)
բարդոյթ (partooyt) “complex”: Ստորակայութեան բարդոյթ (usdoragayootian partooyt “inferiority complex”). This is a relatively new meaning, but only used in a psychological context.
Beware: if you translated terms like “military compound” or “sports complex” into Armenian by using part, nobody would understand you. (You would be using an adjective to translate a noun.) For that, you will have to learn another word: համալիր (hamaleer). For those who have been to Yerevan and have heard of the Hamaleer, there you have it: the sports-musical complex (մարզա–համերգային համալիր/ marza-hamerkayeen hamaleer) located in the hill of Dzidzernagapert, opposite the Մեծ Եղեռնի յուշարձան (Medz Yegherni hushardzan “Great Genocide memorial”) that commemorates 1915.