It was derived from single in-line package.

One variant of the single in-line package uses part of the lead frame for a heat sink tab.

The original memory modules were built upon ceramic and had pins, i.e. single in-line package (SIP) packaging.

One small Basic Atom Pro is implemented as a Single in-line package thus taking very little area on a board, at the expense of greater height.

Single in-line package (SIP)

SIP (Single In-line Package): contains a complete RAM bank.