看到一些递归缩写，很想知道到底有多少缩写是这样的，于是Google了一下，知道了英文说法是Recursive acronym，从Wikipedia上摘录了一些：
递归缩写是一种在全称中递归引用它自身的缩写。因为本身是递归的，所以无法精确地解释出它的真正全称。最早的例子可能是1976年出现的缩写VISA：VISA International Service Association。
给出一些递归缩写：
Cygnus — Cygnus, Your GNU Support (though Cygnus says this is a backronym, while opponents maintain Cygnus, Your GNU Sucks)
EINE — EINE Is Not EMACS
EMACS — EMACS Makes A Computer Slow
GiFT — GiFT: Internet File Transfer, unofficially: "GiFT Isn't FastTrack"
GiNaC — GiNaC is Not a CAS
GNU — GNU's Not UNIX
GNU Hurd — {Hurd = Hird of Unix-Replacing Daemons; Hird = Hurd of Interfaces Representing Depth}
LAME — LAME Ain't an MP3 Encoder
LIAR — LIAR Imitates Apply Recursively
MINC — MINC Is Not C
MINCE — MINCE Is Not Complete EMACS
mung — Mung Until No Good
NiL — NiL Isn't Liero
PHP — PHP: Hypertext Preprocessor
PINE — PINE Is Not Elm
PNG — PNG's Not GIF
RPM — RPM Package Manager
Scaled — Scaled Composites: Advanced Link to Efficient Development
TINT — TINT Is Not Teco
TRM — TRM Recognizes Music
TTP — The TTP Project
VISA — VISA International Service Association
Winamp — WINAMP Is Not An Mp3 Player
WINE = WINE Is Not an Emulator
YAML = YAML Ain't Markup Language
YODL = YODL Online Distributed Ludo
ZARA = ZARA's Against Recursive Acronyms
Zinf — Zinf Is Not FreeA*p!
ZINN = ZINN Is Not Notes
ZWEI = ZWEI Was EINE Initially
可到看到，很多都是平常耳熟能详的名词或软件，比如Cygnus、Emacs、GNU、PHP、PNG、Wine 等等，但你之前知道它的意思吗？