• 赤あか — red
• 赤あかい — red (adjective)
• 赤あかちゃん — baby
• 赤信号あかしんごう — red traffic light
• 赤字あかじ — deficit / red ink
• 赤道せきどう — equator

“赤” is one of Japan’s core traditional colors. Beyond color, it often signals warning, attention, or financial loss — much like in English.