Tathata Ultimate Nature of All Things in Chinese / Japanese...

真如 comes from the Sanskrit and Pali word often romanized as “tathata” or “tathatā.” Originally written, “तथता.”

It's a Buddhist term often translated as “thusness” or “suchness,” but this does not explain it.
A better explanation may be “the ultimate nature of all things” or “ultimate truth.” However, this gives it too strong of a feeling. This concept is sometimes described as being in awe of the simple nature of something - like a blade of grass blowing in the wind or ripples on water. It is what it is supposed to be, these things follow their nature. Amazing in their mundane simplicity.

Every sect of Buddhism will have a slightly different flavor or explanation, so don't get fixated on one definition.

Notes: Sometimes Buddhists use the word dharmatā, a synonym to tathatā.

In Japan, this can also be the female given name Mayuki, or the surname Majo.