When a price is moving upwards and hits a level where it tends to bounce down instead of continuing to rise, that level can be seen as resistance. In other words, the price behaves as if it were resistant to going further up at this point.
Renko Charts explained
Renko charts are concerned with price movement and time is of lesser importance; it is only noted when a new brick is created.
Point and Figure Charts explained
A point-and-figure chart is a graphical representation of price movements that ignore the passage of time.