Many human activities, such as running, walking, or dancing, produce distinctive rhythms, which are often reproduced in music. Rhythm involves not only the positioning or spacing of notes in time, but also their duration, and both of these can be notated in Western music (see p.15).
The pulse (commonly known as the “beat”) is a regular unit of time around which the rhythm of a piece is organized. In a march, this would be the position in time of each footstep. The composer decides whether the pulse should be a half or a quarter, or any other note value. The speed of the pulse is the “tempo” of the work. Most composers have used Italian terms (see p.14) to indicate tempo.
The meter corresponds to the grouping of the pulse. Much Classical music is grouped in twos or threes. Each group is known as a “measure” or “bar” and in notation is separated by a “barline." The meter is indicated by a “time signature,” such as 3/4. The top number shows the number of beats in the measure, while the lower number shows the value assigned to each beat.
Please see the titled question, as the overhead doesn't distinguish meter vs. rhythm.
I deliberately chose this book's definitions; I'm trying to compare definitions across introductory books for laypeople.