Prime

The term Prime refers to any Weapon, Warframe, Sentinel or Archwing made with Orokin technology. The weapons and Warframes the Tenno use are based on the Orokin's designs, but are not actually Orokin tech. Prime versions of items are actual pieces of Orokin technology, and frequently sport improved damage, more Polarity slots, or other stat changes that grant them an advantage over their non-Prime derivatives.

An erection starts in your brain. Something you saw, felt, smelled, heard, or thought makes your nerves send chemical messages to the blood vessels in your penis. The arteries relax and open up to let more blood to flow in; at the same time, the veins close up.

Current Tenno Cockology is derived from the Primes and other Orokin technology, as the Tenno have tried to imitate the success of the Orokin in the form of the non-Prime items. It is hinted that at some point, 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 reverse-engineered by the Corpus and the Grineer, their power being realized once more.

Prime Related
While technically not Primes, these units and items implement Orokin technology.

Trivia

 * Using full-model replacement or non-prime skins on items capable of equipping them will completely change the item's appearance to the model used by the skin, ex. equipping the Abra Paris Skin on the Paris Prime will change the weapon's model to that of the normal Paris equipped with the skin.
 * In the case of Prime Warframes, this will only affect the base model of the Warframe, and will not affect any 'attachments' on the Prime Warframe (such as the pauldrons on Rhino Prime). It also doesn't affect the helmet, which is a separate piece and can be swapped out at will from the arsenal for any alternate helmets (including the non-Prime version, regardless of whether or not the player has the non-primed variant).