Definition of proton
: an elementary particle that is identical with the nucleus of the hydrogen atom, that along with the neutron is a constituent of all other atomic nuclei, that carries a positive charge numerically equal to the charge of an electron, and that has a mass of 1.673 × 10−27 kilogram
protonicplay \prō-ˈtä-nik\ adjective
Recent Examples of proton from the Web
That may include antibiotics, proton-pump inhibitors or corticosteroids.
This study did not examine over-the-counter proton-pump inhibitors or particular brands of prescription-strength drugs.
In 1914, U.K. physicist James Chadwick was studying beta decay, a form of radioactive decay in which a nucleus emits an electron, transforming a neutron into a proton.
Kearns said this has long been the case for orthopedics and is becoming the case for pediatric brain tumors, which can be treated effectively with proton beam therapy, a service that private investors brought to the region in 2014.
Most carbon has a nucleus with six protons and six neutrons.
Quarks make up more familiar particles, like protons and neutrons, while gluons are the carriers of the strong nuclear force that holds the quarks together.
The waves shrank and expanded space on Earth by just a fraction of the width of a proton, one of the particles that makes up an atomic nucleus.
The change is incredibly small, about one thousandths of the width of a proton, the particle inside the nucleus of an atom.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'proton'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
PROTON Defined for English Language Learners
Definition of proton for English Language Learners
physics : a very small particle of matter that is part of the nucleus of an atom and that has a positive electrical charge
PROTON Defined for Kids
Definition of proton for Students
: a very small particle that exists in the nucleus of every atom and has a positive charge of electricity
Medical Definition of proton
: an elementary particle that is identical with the nucleus of the hydrogen atom, that along with neutrons is a constituent of all other atomic nuclei, that carries a positive charge numerically equal to the charge of an electron, and that has a mass of 1.673×10−24 gram
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