yogurt; a fermented dairy product; also known as [[酸乳|酸乳|suan1 ru3]] or [[酸牛奶|酸牛奶|suan1 niu2 nai3]]

to feel grieved or bitter; to be touched with sadness or sorrow

Organic compounds that contain both amino and carboxyl groups, serving as the fundamental building blocks of proteins.

an inorganic strong acid (H2SO4) that is a colorless, oily liquid widely used in manufacturing fertilizers, dyes, and explosives

an inorganic acid used for making fertilizers, dyes, medicines, and fireworks; it appears as colorless crystals or a thick liquid and is easily dissolved by water in the air

hydrochloric acid; an aqueous solution of hydrogen chloride (HCl). A strong inorganic acid used widely in industry and medicine; also known as [[氢氯酸|氫氯酸|qing1 lu:4 suan1]] or [[盐强水|鹽強水|yan2 qiang2 shui3]].

the chemical property of being acidic; having a sour taste, being able to neutralize bases, and turning blue litmus paper red

to be sore and aching; to feel a dull pain in the muscles or joints

pungent and sour in taste; hot and tart

General term for any organic acid found in fats and oils; usually refers to chain-like carboxylic acids which are the building blocks of lipids in animals, plants, and microorganisms.

carbonic acid; a weak inorganic acid formed by dissolving [[二氧化碳|二氧化碳|er4 yang3 hua4 tan4]] in water, used in making soft drinks and chemicals

pickled vegetables, especially Chinese cabbage, that have been fermented until they become sour

a colorless or pale yellow organic acid widely found in living organisms and produced via fermentation; commonly used in the food, textile, and pharmaceutical industries

A colorless or pale yellow corrosive strong acid with a sharp smell; widely used in manufacturing fertilizers, explosives, and chemicals.

acetic acid; acetate; also known as [[乙酸|乙酸|yi3 suan1]]

An organic compound found in the cells of all living things and viruses, essential for growth, reproduction, and heredity.

stomach acid; hydrochloric acid found in gastric juices that aids in digestion and kills bacteria

folic acid; folacin; an essential B vitamin found in leafy green vegetables, liver, and beans that is necessary for cell growth and division

a white crystalline organic compound found in small amounts in the urine and blood of humans and animals; excessive levels in the blood can lead to kidney stones or gout

the four basic tastes of sour, sweet, bitter, and spicy, used to describe a complex variety of flavors in food

nitrous acid (HNO2); a light-blue chemical solution often used as a reducing agent in industry

The basic building block of nucleic acids like DNA and RNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

acetic acid; ethanoic acid; a colorless liquid with a pungent smell that is the main component of vinegar

sharp and sarcastic; describes a tone of voice or remarks that are harsh or acrimonious

aching waist and sore back; used to describe general body aches and pains, often from overwork or fatigue

methanoic acid; the simplest carboxylic acid, naturally occurring in the stings of ants and bees, used widely in the leather and dye industries

sour with a hint of sweetness; sweet and sour

An organic compound occurring naturally in citrus fruits, used as a food additive and for industrial cleaning; also called [[枸橼酸|枸櫞酸|ju3 yuan2 suan1]].

a feeling of deep distress or grievance

miserable and poor, originally describing the distressed appearance of a poor scholar

An amino acid that plays an important role in protein metabolism; its sodium salt is used to make [[味精|味精|wei4 jing1]]

Rain, snow, or fog that has been made acidic by air pollution from burning fossil fuels; also called [[酸性雨|酸性雨|suan1 xing4 yu3]]

oxalic acid; a colorless, toxic organic compound used for bleaching, dyeing, and removing rust

Bacteria that break down carbohydrates to produce lactic acid, such as lactobacillus; used in food fermentation and yogurt production.

sour flavor; tartness; acidity

lysine (Lys); an essential amino acid necessary for human health

any salt or ester of phosphoric acid

tyrosine (Tyr), a non-essential amino acid used in the biosynthesis of proteins

benzoic acid (C6H5COOH)

the concentration of acid in a substance; the degree of sourness

arginine (Arg), an amino acid

to acidify; to acidize; the process of becoming or making something acidic

Any of a large group of chemical compounds containing silicon and oxygen; the main components of the Earth's crust, including minerals like mica and feldspar.

A general term for acidic organic compounds, such as fatty acids or carboxylic acids; widely used in the production of dyes, medicines, and plastics

calcium carbonate; a white solid substance insoluble in water that is used to manufacture cement, ceramics, lime, and medicinal products

to ferment and develop a sour taste; to become acidic

sore and weary in the body or limbs; limp and aching

having a sour and astringent or acrid taste