Liquid propellant - Ekitai Suiyaku

...In both the liquid and solid cases, there are those that utilize the exothermic reaction of a single substance; in the liquid case it is called a monopropellant, and in the solid case it is called a homogeneous system. Most commonly, an oxidizer and a fuel are used in combination; the combination of liquid and liquid and solid and solid are called liquid propellants and solid propellants, respectively, and the combination of liquid and solid is called a hybrid propellant (propellant is sometimes called rocket fuel, but strictly speaking rocket fuel refers to the fuel that is one component of propellant). These combinations do not necessarily have to be one type of oxidizer and one type of fuel; particularly in the case of solids, it is common to use a mixture of several components, which is called a hybrid system.

*Some of the terminology that refers to "liquid propellant" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…液体と固体の場合，いずれについても単一物質の発熱反応を利用できるものがあり，液体ではモノプロペラント，固体では均質系と呼ばれる。もっともふつうには酸化剤と燃料を組み合わせて用い，液体と液体，固体と固体の組合せをそれぞれ液体推薬，固体推薬といい，また，液体と固体との組合せをハイブリッド推薬という(推薬をロケット燃料と通称することもあるが，厳密にはロケット燃料とは推薬の1成分である燃料を指す)。これらの組合せは必ずしも酸化剤，燃料それぞれ一種ずつとは限らず，とくに固体では数種の成分の混合物とするのがふつうで，これを混成系という。…

※「液体推薬」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報