Tilda is a GTK+

GTK+

GTK+ is a cross-platform widget toolkit for creating graphical user interfaces. It is licensed under the terms of the GNU LGPL, allowing both free and proprietary software to use it. It is one of the most popular toolkits for the X Window System, along with Qt.The name GTK+ originates from GTK;...

 terminal emulator

Terminal emulator

A terminal emulator, terminal application, term, or tty for short, is a program that emulates a video terminal within some other display architecture....

. Its design was inspired from consoles in computer games such as Quake

Quake (series)

The Quake series is a line of first-person shooter video games produced by id Software.-Overview:The Quake series is somewhat unusual in that its focus changes frequently; the story of Quake II has nothing to do with Quake, and Quake III Arena has little to do with either of its predecessors...

 which slide down from the top of the screen when a key is pressed, typically the tilde

Tilde

The tilde is a grapheme with several uses. The name of the character comes from Portuguese and Spanish, from the Latin titulus meaning "title" or "superscription", though the term "tilde" has evolved and now has a different meaning in linguistics....

, and slide back up when the key is pressed again.

Running Tilda can be faster than launching a new terminal with a keyboard shortcut

Keyboard shortcut

In computing, a keyboard shortcut is a finite set of one or more keys that invoke a software or operating system operation when triggered by the user. A meaning of term "keyboard shortcut" can vary depending on software manufacturer...

 because the program is already loaded into memory; it can be useful to people who frequently find themselves opening and closing terminals for odd tasks.

It is free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

 licensed under the terms of the GNU General Public License

GNU General Public License

The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....

.

Terminal Emulators

• List of terminal emulators
• Guake
  Guake
  Guake is a drop-down terminal for GNOME Desktop Environment. Like similar terminals, it is invoked with a single keystroke, and hidden by pressing the same keystroke again....
  
   - The same function under GNOME
  GNOME
  GNOME is a desktop environment and graphical user interface that runs on top of a computer operating system. It is composed entirely of free and open source software...
  
  
• stjerm - Another drop-down terminal
• Yakuake
  YaKuake
  Yakuake is a KDE terminal emulator. Its design was inspired from consoles in computer games such as Quake which slide down from the top of the screen when a key is pressed, and slide back up when the key is pressed again....
  
   - The same function under KDE
  KDE
  KDE is an international free software community producing an integrated set of cross-platform applications designed to run on Linux, FreeBSD, Microsoft Windows, Solaris and Mac OS X systems...
  
  
• Visor http://visor.binaryage.com/ - The same function for Mac OS X
  Mac OS X
  Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
  
  
• aterm
  Aterm
  aterm is the AfterStep terminal emulator for the X Window System. Based on rxvt 2.4.8 , aterm is a color VT100 terminal emulator that supports basic pseudo-transparency....
  
  
• Eterm
• rxvt
  Rxvt
  rxvt is a terminal emulator for the X Window System , originally written by Rob Nation and later extensively modified by Mark Olesen, who took over maintenance for several years...
  
  
• xterm
  Xterm
  In computing, xterm is the standard terminal emulator for the X Window System. A user can have many different invocations of xterm running at once on the same display, each of which provides independent input/output for the process running in it .xterm originated prior to the X Window System...
  
  
• Konsole
  Konsole
  Konsole is a free terminal emulator which is part of KDE Software Compilation. Konsole was originally written by Lars Doelle.The KDE applications Konqueror, Krusader, Kate, Konversation, Dolphin and KDevelop use Konsole to provide embedded terminal functionality.- Features :* Tabbed terminals...