Chemistry Dictionary A–Z Terms

Chemistry Dictionary is an offline chemistry glossary of 683 chemistry terms from A to Z, each explained in clear, plain English.
Look up the meaning of any term, from absolute zero to zwitterion, with its symbol, formula or chemical equation where it helps.

Every entry gives a short definition written for students, often with an example, and ends with "See also" links to related terms, so one definition leads naturally to the next. 135 entries include a typeset formula or equation and 95 show the symbol of the quantity.

What you will find

• A–Z Dictionary: 23 letter pages, each with a filter box, so you can find any chemistry term in seconds
• Browse by Topic: the chemistry terms of each field gathered on one page: Matter, Measurement and Reactions (87 terms); Atoms and the Periodic Table (83); Bonding and Molecular Shape (74); States of Matter and Solutions (115); Energy, Rates and Equilibrium (80); Acids, Bases and Electrochemistry (87); Elements and Inorganic Chemistry (65); Organic Chemistry and Biochemistry (101); Nuclear Chemistry (37); and Lab Equipment and Techniques (90)
• 25 key drawings on the topic pages, including the periodic table by block, orbital shapes, VSEPR molecular shapes, the phase diagram of water, energy profiles, titration curves, a galvanic cell, functional groups, half-life and laboratory glassware
• SI Units and Constants: the 7 SI base units, derived units, 14 constants with CODATA 2022 values from NIST and the gas constant in different units
• Elements: all 118 elements with symbol, name and IUPAC 2021 standard atomic weight
• Common Ions: cations, anions and polyatomic ions with their names and charges
• Prefixes and Greek Letters: all 24 SI prefixes, prefixes for naming compounds, carbon-chain stems and the Greek alphabet

Examples of terms in the dictionary
• Atoms and bonding: electron configuration, ionization energy, electronegativity, covalent bond, hydrogen bond, VSEPR theory
• Reactions and amounts: mole, Avogadro constant, molarity, stoichiometry, limiting reactant, oxidation number
• Energy and equilibrium: enthalpy, activation energy, catalyst, equilibrium constant, Le Chatelier's principle, pH
• Organic and lab chemistry: functional group, isomers, polymer, titration, chromatography, distillation

Features
• 683 chemistry definitions in plain language, with every symbol explained
• Formulas and chemical equations typeset to stay sharp on any screen
• Sign conventions stated where textbooks differ
• Search the whole dictionary from the home screen, plus a filter on every letter page
• Dark mode
• Works offline, no account needed
• Available in 8 languages: English, Español, Português, Français, Deutsch, العربية, हिन्दी and Bahasa Indonesia. In every language, terms can be found by their English or translated name, which also makes the app a handy English chemistry vocabulary list

Who it is for
• High school students who meet a new chemistry term in class or in a textbook
• College and university students in introductory chemistry
• Students reading chemistry in a second language who need the English term next to their own
• Teachers and tutors who want a reliable chemistry glossary to point students to
• Useful when revising for school chemistry, AP, A-level or IB exams and introductory university chemistry

Chemistry Dictionary is an independent study aid. Definitions follow the OpenStax Chemistry 2e textbook and IUPAC recommendations; constants are the NIST CODATA 2022 values and atomic weights the IUPAC 2021 standard values. It is not affiliated with any exam board, textbook publisher or standards body.