Wa
Wa can mean harmony as in Wa Kei Sei Jaku (和敬清寂), the famous principles of tea. It can also mean Japan as in Wamono (The Chinese used a different Wa when they first called Japanese that, this Wa meant hairy dwarf, Japanese scholars who studied in China discovered this and found a different kanji with the same pronunciation, the wa of harmony.)
In tea it is usually taken to mean harmony and oneness with nature and people, a harmonious spirit between host and guest, guest and guest.