Meaning
The kanji 太 means fat, thick, large, and great. It covers two distinct ideas: physical bulk (a thick rope, a tree too wide to hug, a person who gained weight) and grand scale (the sun, the Pacific Ocean, an ancient era). Few 4-stroke kanji carry this much range.
太 comes from 大 (big), with one extra stroke signaling something beyond ordinary size — not just large, but overflowing. Visually: 大 shows a person standing with arms wide. Add a mark below, and that person grew a belly. That extra stroke is the whole idea.
Four strokes, Grade 2 curriculum. Japanese children learn 太 early — and with good reason. It shows up in words you can't avoid: the sun (太陽), the Pacific Ocean (太平洋), the crown prince (皇太子). For such a simple character, its reach is remarkable.
日常会話 and formal writing both use 太 constantly — as a standalone adjective (太い, thick or fat) and inside compound words. Spot it in a word, and expect something vast, physically substantial, or historically weighty.
Readings
On'yomi (音読み) — Chinese-derived readings
The on'yomi readings are タイ and タ, both from ancient Chinese. They appear in compound words (熟語, jukugo) of Chinese origin.
タイ (TAI) — The dominant on'yomi, found in major vocabulary:
- 太陽 (taiyou) — the sun; literally "great light"
- 太平洋 (taiheiyou) — the Pacific Ocean; literally "great peaceful ocean"
- 太古 (taiko) — ancient times, antiquity
- 皇太子 (kōtaishi) — crown prince
タ (TA) — Rarer, but essential for one key word:
- 太刀 (tachi) — a long Japanese sword, historically significant in samurai culture
Kun'yomi (訓読み) — Native Japanese readings
The kun'yomi are ふと.い (futoi) and ふと.る (futoru) — used when the kanji stands alone or takes hiragana endings (okurigana).
ふと.い (futoi) — an i-adjective meaning thick, fat, or stout. Applies to objects and bodies alike:
- 太い腕 (futoi ude) — thick, muscular arms
- 太い声 (futoi koe) — a deep, resonant voice
- 太い木 (futoi ki) — a thick tree trunk
ふと.る (futoru) — to gain weight, get fat. You'll hear this constantly in conversations about food, diet, and body image:
- 太る (futoru) — to gain weight
- 太りすぎ (futorisugi) — overweight, too heavy
- 太り気味 (futori gimi) — tending to be on the heavier side
Common Words & Compounds
Nature & Geography
- 太陽 (taiyou) — the sun
- 太平洋 (taiheiyou) — the Pacific Ocean
- 太陽系 (taiyoukei) — the solar system
- 太陽光 (taiyoukou) — sunlight, solar light
History & Culture
- 太古 (taiko) — ancient times, antiquity
- 太鼓 (taiko) — Japanese drum (note: same reading, different kanji 鼓)
- 太刀 (tachi) — long sword (over 60 cm), worn by samurai
- 皇太子 (kōtaishi) — crown prince
Everyday Words (Body & Shape)
- 太い (futoi) — thick, fat, stout
- 太る (futoru) — to gain weight
- 太め (futome) — on the thick or heavy side
- 丸太 (maruta) — a log, a round piece of timber
Peace & Grandeur
- 太平 (taihei) — peace, tranquility
- 太平楽 (taiheiraku) — carefree, at ease (often used ironically)
Example Sentences
この木は太くて、一人では抱きかかえられない。
Kono ki wa futokute, hitori de wa dakikakaerare nai.
This tree is so thick that one person can't wrap their arms around it.
最近、食べすぎて太ってしまった。
Saikin, tabesugite futotte shimatta.
I've been eating too much lately and ended up gaining weight.
太陽は毎朝東から昇ります。
Taiyou wa maiasa higashi kara noborimasu.
The sun rises from the east every morning.
彼は太い声で歌を歌った。
Kare wa futoi koe de uta wo utatta.
He sang the song in a deep, full voice.
太平洋は世界で一番大きい海です。
Taiheiyou wa sekai de ichiban ookii umi desu.
The Pacific Ocean is the largest ocean in the world.
甘いものを食べすぎると太りますよ。
Amai mono wo tabesugiru to futorimasu yo.
Eat too many sweets and you'll gain weight, you know.
太鼓の音が遠くまで聞こえた。
Taiko no oto ga tooku made kikoeta.
The drum could be heard from far away.
太めのペンで名前を書いてください。
Futome no pen de namae wo kaite kudasai.
Please write your name with a thicker pen.
太陽エネルギーは環境にやさしいです。
Taiyou enerugii wa kankyou ni yasashii desu.
Solar energy is kind to the environment.
丸太を使って小屋を建てた。
Maruta wo tsukatte koya wo tateta.
They built a cabin using logs.
Related Kanji
- 物 — Thing, Object, Matter (Kanji N4)
- 夏 — Summer (Kanji N4)
- 田 — Rice Field (Kanji N4)
- 薬 — Medicine, Drug (Kanji N4)
- 妹 — Younger Sister (Kanji N4)
- 地 — Ground, Earth, Land (Kanji N4)
Memory Tip
Picture 大 as a person standing with arms stretched wide. Add a small mark below — that person just ate too much and grew a round belly. Now you have 太: fat, round, full.
The same logic extends outward. 太陽 is the ultimate great body of light. 太平洋 is the ocean at its most vast. Whenever you spot 大 carrying that extra mark, think: 大 pushed past its limit — bigger, rounder, more.