The isolated pawn or “isolani” is a pawn that can’t be protected by a fellow pawn. The isolani used to be considered a weakness, and is almost always a weakness in the endgame. However, in the middle game, an isolani can also be an asset. If the player with the isolani avoids too many piece exchanges, she may be able to use the isolani as a support base, a battering ram or for some other purpose to assist her pieces in the attack. So if you choose to play with the isolani, you have to be aware that you need to convert it into an advantage during the middlegame, otherwise you’ll end up with a weak pawn in the endgame.
If you play against an isolani, your plan often entails immobilising it and then besieging it with your pieces, forcing your opponent into a passive defence. The gif above illustrates this idea during the opening phase: when you see that the upcoming pawn exchanges leads to an isolani on your opponent’s side, consider fianchettoing the bishops to attack the isolani from the flank.
On a related note: Temposchlucker mentioned in a comment that his goal is “to recognize all kinds of characteristics of a position”. Incidentally, Blue Devil Knight posted a quote by Jonathan Rowson on the danger of evaluating a position on the basis of words and explanations rather than moves:
[T]hinking of such models explicitly while your clock is ticking will generally do more harm than good. Anything other than the images of moves and variations is likely to be unhelpful noise in your head that will lead you to create narratives based on applying the model to the position. This awkward predicament leads you to try to fit the position to what is in your head, rather than allowing you to concentrate on the position and enjoy the experience of playing…[Y]ou will gain more from the material in this chapter if you allow it to ‘seep in’ subtly and quietly, rather than using it as some kind of checklist during your games.
Rowson’s warning struck a chord with me. I used to make up such “position narratives” all the time, and the reason, I believe, was that I saw no meaningful candidate moves, so I tried to make some of the available moves meaningful by constructing a narrative around them. Part of what I’m trying to achieve with the Chunky Rook is to learn more concrete and substantial narratives, namely narratives that are associated with specific positions and specific move sequences. The fianchettoed bishop against isolated pawns is one example for this.