Pentatonic scale
Pentatonic scale, or Pentatonic mode, is a mode that contains only 5 notes (sounds). So all modes with 5 sounds can be called pentatonic modes.
Pentatonic scales were developed independently by many ancient civilizations and are still used nowadays, for example in Chinese music or in Blues music (US).
Major pentatonic scale
Below is the Major pentatonic scale:

This pentatonic scale is described as Major because of its [url_id=710]major third[/url_id].
The Major pentatonic scale is in fact the five first notes on the circle of fifths starting from C note:
Minor pentatonic scale
Below is the minor pentatonic scale:

The note of the minor pentatonic scale are the same as in the Major pentatonic scale but starting from a different note.
This pentatonic scale is described as minor because of its minor third.
Below is the minor pentatonic scale starting from C note:
Major and minor pentatonic scale on a piano keyboard
It is very easy to find the pentatonic scale on a piano keyboard, you can use only black keys:
Starting from F♯: F♯ G♯ A♯ C♯ D♯ is the Major pentatonic scale
Starting from D♯: D♯ F♯ G♯ A♯ C♯ is the minor pentatonic scale
Example of pentatonic scale in classical music
Here is an example of pentatonic scale in classical music:

It is an excerpt of the "American" quartet Opus 96 Number 12 by Anton Dvorak int the Allegro moderato movement played by the viola.
For easiest reading, below is a transposed version:

You can read on this transposed excerpt the major pentatonic scale:

Transposed major pentatonic scales
Below are all transposed major pentatonic scales:
Transposed minor pentatonic scales
Below are all transposed minor pentatonic scales:
External links to learn more about :
1 - https://musicterms.artopium.com/p/Pentatonicscale.htm
2 - https://en.wikipedia.org/wiki/Pentatonic_scale
3 - https://www.dolmetsch.com/musictheory25.htm#pentatonic