Let us look at both Pra and dakshiNam forming the word, PradakshiNam. Pra as an adjective means very much. Pra can also come as a prefix to verbs and take on the meaning of onward, forward. Onward to DakshiNam or south is pradakshiNam . When one does that, one's right side is facing the Moolavar inside the garbhagraham and the circumambulation is DakshiNAchAram or auspicous as recommended by the vedam . Alternatives are VaamAchAram and are taantric in character.
Unaadi soothrAs break up the word DakshiNa into Daksh+iNan , meaning as being situated in the South . Dakshina also means sincere, auspicious , dextrous and the Southern sacred fire (DakshiNAgni , one of the three VaidhigAgnis ) used in Vedic sacrifices . Although we can elaborately study the connections of these different meanings to the auspicious act of PradkshiNam , we will focus on the Rg Vedic Usage of the word of pradakshiNam in its second KhANdam . Yajn~yavalkya smruthi defines PradakshiNam as the act of circumambulation , where one's right side is facing the object or person. PradakshiNam around the fire in Vedic marriages or PradakshiNam of a sacred hill like Thirumalai or PerumAL' s garbha graham follows this rule to assure auspiciousness. The opposite is amangaLam.
Coming to the Rg Vedic verses (Rg: 2.42.3 and 2.43.1), we can see the Vedic context of PradakshiNam .
Here Vedhic pasage equates the Jeevan sitting inside the cage of body as the voice of inner consciousness and an auspicious one ( BhadravAdhI sakunthE ). The entire Rk praying to that inner conscience is (Rg Vedam -2.42.3):
(Meaning):" O Sacred Bird (the voice of inner conscience), the proclaimer of all that is good , benign and benevolent , may you cry(speak) from the right (or south) of our dwellings (or hearts). May no thief , no evil doer, prevail against us. May we, blessed with excellent descendents , worthily praise you in this assembly of devotees ".