There is a difference between washing and wiping in terms of language and usage. The difference between washing and wiping is that washing involves water flowing over the body part, while wiping involves passing a wet hand over the body part. Washing requires pouring water over the body part using the hand or a flowing device like a tap, whereas wiping does not require pouring water, but just dipping the hand in water and passing it over the body part.
The second difference is that washing can be repeated two or three times, while wiping is disliked to be repeated because it is based on ease and repetition would turn it into washing.
The third difference between washing and wiping is that washing does not require passing the hand over the washed body part, and it is sufficient to pour water over it according to the majority opinion (contrary to the opinion of the Malikis). On the other hand, wiping requires passing the wet hand over the body part in wudu, and touching the dust in case of tayammum (dry ablution).
Fatwa by Dr. Khālid Naṣr