accord

What it means

1. countableuncountableAgreement of opinion, will, or action.

   a mediator of an accord and peace between them

   1622, Francis, Lord Verulam, Viscount St. Alban [i.e. Francis Bacon], The Historie of the Raigne of King Henry the Seventh, […], London: […] W[illiam] Stansby for Matthew Lownes, and William Barret, →OCLC

   1 more example

   These all continued with one accord in prayer and supplication, with the women, and Mary the mother of Iesus, and with his brethen.

   1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC, Acts 1:14

   Synonyms: consent, assent

2. countableuncountableentertainmentAgreement in pitch and tone; harmony, musical concord.

   Those sweet accords are even the angels' lays.

   17th century, Sir John Davies, The Self-Subsistence of the Soul

   1 more example

   In a languid and mysterious chant Sister Clara raised her voice, and her acolytes kept accord on their mandolines […].

   1917, Aleister Crowley, Moonchild, Weiser, published 2010, page 146

3. countableuncountableAgreement or harmony of things in general.

   the accord of light and shade in painting

In a sentence

These all continued with one accord in prayer and supplication, with the women, and Mary the mother of Iesus, and with his brethen.

1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC, Acts 1:14

Where it comes from

1. Old Frenchacort
2. Middle Englishaccord
3. Englishaccord

From Middle English accord, from Old French acort, from acorder (see verb below).