All Time High (ATH)
All Time High, often shortened as ATH, is the highest price an asset has reached in its lifetime. For example, the Japanese Nikkei 225 (a fund tracking the top 225 Japanese companies) peaked at 40,000 in the 1980's. It has not ever been higher than that, either before, or in the decades after it. That makes 40,000 its All Time High.