Quote：- “ Is there a Chinese word for the Japanese 気合。。。？“
This is a damn good question. I've never thought about this until now.
Having practiced Chinese, (洪拳), Japanese, (Judo), and Korean, (Taekwondo, holding a Black Belt), I am familiar with the practical aspects of "Kiai". The Koreans have a direct equivalent called 기합, (Kihap), (气合), but for some reason there is no direct Chinese terminological equivalent.
But having said that, I do know that some, (not all), Chinese martial artists do use a more descriptive term, namely, 发声, (Fa Sheng), meaning to issue, to emit, to send out sounds while performing their preset Forms, or presumably in combat, if ever the situation arises.
I do not wish to go into the martial aspects of it as this is not the proper forum, but I would just surmise that the reason why there isn't a direct comparable term in Chinese martial arts to "Kiai" is because of the historically diverse, disorganized and secretive nature of the numerous Chinese arts stretching across the whole continent of mainland China, (there are literally hundreds of individual arts practiced in practically every village), that there isn't a central governing body to standardized the technical terms or practice of the numerous art, (which is impossible as no two arts are exactly the same, though the Chinese government around the 1950s & 60s tried and the mishmash art officially called "Wu Shu", （武术），was born and now in the Olympics)
So, while practitioners of the Chinese arts may know exactly what it means in practice, nobody actually coined an "official" word for it, unlike the more insular and better organized Japanese and Koreans.
Hence in my own training the Chinese master simply ordered "Ahhhheeee....!", and we "Ahhhheeeee..., without asking him what this shout is called. It was only when I later took up the Japanese and Korean arts did I know it's actually called "Kiai" or "Kihap"