水系(すいけい)

すいけい
noun
water system; river system; watershed
geography
1. river system; water system; watershed
the network of rivers, tributaries, and streams that drain into a single body of water
利根川(とねがわ)水系(すいけい)は日本最大(にほんさいだい)だ。
The Tone River system is the largest in Japan.
この地域(ちいき)は複数(ふくすう)の水系(すいけい)にまたがっている。
This region spans multiple river systems.
水系(すいけい)ごとに水質(すいしつ)の管理(かんり)が行(おこな)われている。
Water quality management is conducted for each river system.
2. water-based; aqueous (as prefix)
used as a prefix to indicate something is water-based, as opposed to oil-based or solvent-based
水系(すいけい)インクは乾(かわ)きが遅(おそ)い。
Water-based ink dries slowly.
水系(すいけい)の塗料(とりょう)はにおいが少(すく)ない。
Water-based paint has less odor.
環境(かんきょう)への配慮(はいりょ)から、油性(ゆせい)ではなく水系(すいけい)の洗剤(せんざい)を選(えら)ぶ企業(きぎょう)が増(ふ)えている。
Due to environmental considerations, more companies are choosing water-based detergents over oil-based ones.

Composed of 水(すい) (water) + 系(けい) (system; lineage). The two senses are quite distinct: the geographical meaning refers to river networks, while the chemical/industrial meaning indicates a water-based substance.

Common collocations

Similar words

  • 流域(りゅういき): river basin; drainage area — refers to the land area rather than the network of waterways
  • 油性(ゆせい): oil-based — the antonym of 水系(すいけい) in the chemical/industrial sense
  • 水性(すいせい): water-based; aqueous — a near-synonym of sense 2, more common in consumer products (e.g., 水性(すいせい)ペン)

Related Words

Compare: 流域(りゅういき) (river basin)
Compare: 油性(ゆせい) (oil-based)
general
Added 2026.5.1 0:27 · Revised 2026.9.2 13:02
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