A strategy role-playing game (SRPG), also known as tactical role-playing game, is a role playing game that also involves strategic troop movement. There are several distinct approaches to this genre, but they all boil down to the same concept: more strategy than a traditional RPG.
The most typical approach is that a party member is regarded on the battle field as that member's avatar, and combat takes place on the battle field with no screen changes. Generally, when a member's turn comes up, the player has the option of moving him or her (within a certain range, depending on the character's statistics, equipment, class, et cetera), the option of performing an action - using an item, using a basic attack, or performing a special move - and the option of facing the party member in a certain direction. Most SRPGs make a distinction between attacking an enemy from the front, from the sides, or from the rear, to add more tactical advantage to good movement strategies.
A less popular but also fairly common approach is to regard a unit or group of units as a battle field avatar, which is ordered to move about in a similar action, but performs a screen change in combat. In some titles, as in Fire Emblem, units will then exchange some fire automatically, their statistics will be changed accordingly, and the game proceeds on its merry way. In some others, as in Bahamut Lagoon, the battle screen actually becomes a single turn of a traditional RPG battle; the player selecting a move for each character in the party, and the enemy doing the same.
Battle fields for the first approach, as it revolves around characters, tend to be small and personal. Terrain is usually used to make strategic advantages - for instance, a character on the higher ground of a slope will fare better than his opponent on lower ground. Different types of terrain are also frequently used, like water which can impede movement, and steps that take extra time to move over.
Fields for the second approach, that one revolving more around larger forces (usually, a small army), tend themselves to be more expansive. They also use terrain differences, but being on a grander scale, differentiate between things like rivers, plains, forests, and mountains.
In both fields, some games take an interactive approach with magic - i.e. fire magic can burn plants, and ice magic can freeze water. The SRPG genre is fairly small, and so not only is it relatively easy (aside from all the work involved) to make one very unique, but new ideas for making the games more strategic are always being found.
Most SRPGs have a title that includes the word "Tactics" (e.g. Final Fantasy Tactics, Tactics Ogre, Onimusha Tactics, Dynasty Warriors Tactics, et al.). Other examples include the Fire Emblem series and Nippon Ichi's games (like Disgaea: Hour of Darkness and Phantom Brave).