The term Prime refers to any Weapon, Warframe, Sentinel, Archwing, or accessory made with Orokin technology. The non-Prime weapons and Warframes the Tenno use are based on the Orokin’s designs, but are not actual pieces of Orokin technology. Primes frequently sport improved damage, more Polarity slots, or other stat changes that grant them an advantage over their non-Prime derivatives.
The Tenno have tried to imitate the success of Orokin technology in the form of the non-Prime items, resulting in slightly weaker variations. The Tenno were once capable of creating Primes of their own, examples being the Boar, Dakra, and the Kamas, however, such knowledge is now lost. With the rediscovery of the Void, many Prime items are being reclaimed by the Tenno and/or reverse-engineered by the Corpus and the Grineer, the strength of their craftsmanship being realized once more.