
Origin of the Name Rainey
The origin of the name 
Rainey was found in the allfamilycrests.com archives. 
Over the centuries Surnames developed  a wide number of variants. Different spellings of the same name can be traced back to an original root. Additionally when a bearer of a name emigrated it was not uncommon that their original name would be incorrectly transcribed in the record books at their new location. Surnames were also often altered over the years  based on how they sounded phonetically and depending on the prevailing political conditions it may have been advantageous to change a name from one language to another.
Variants of  the name Rainey
 include Rainy, Rainie, Raine, Rainnie, Rigney, Rennie and Renny. These names are derived from the Gaelic O'Raighne sept that was located in County Westmeath in Leinster  Province in Ireland . 
A sept or clan is a collective term  describing a group of persons whose immediate ancestors bore a common surname and inhabited the same territory. Irish  septs and clans that are related often belong to even larger groups, sometimes called tribes.
 The placename Clonyrina in Westmeath specifically marks their location. This placename in Gaelic is 'Cluain Ui Raighne' meaning 'Raighne's fort'. Other families of the name Rainey were introduced into Ulster  Province by settlers who arrived from England  and Scotland , especially during the seventeenth century. When of Scottish and English origin the name can also be a variant of the surname Renny and Rennie.
The Rainey coat of arms came into existence centuries ago. The process of creating coats of arms (also often called family crests) began in the eleventh century although a form of Proto-Heraldry may have existed in some countries prior to this. The new art of Heraldry made it possible for families and even individual family members to have their very own coat of arms, including all Rainey descendants.