
The English word Maundy in that name
for the day is derived through Middle English, and Old French mandé, from the
Latin mandatum, the first word of the phrase "Mandatum novum do vobis ut diligatis
invicem sicut dilexi vos" ("A new commandment I give unto you, That ye love
one another; as I have loved you"), the statement by Jesus in the Gospel of
John (13:34) by which Jesus explained to the Apostles the significance of his
action of washing their feet. This is the definition of the word "maundy", according
to a common theory.
The phrase is used as the antiphon sung
during the "Mandatum" ceremony of the washing of the feet, which may be held
during Mass or at another time as a separate event, during which a priest or
bishop (representing Christ) ceremonially washes the feet of others, typically
12 persons chosen as a cross-section of the community.
According to other authorities, the English
name "Maundy Thursday" arose from "maundsor" baskets, in which on that day the
king of England distributed alms to certain poor at Whitehall: "maund" is connected
with the Latin mendicare, and French mendier, to beg. A source from the Missouri
Synod of the Lutheran Church likewise states that, if the name were derived
from the Latin mandatum, we would call the day Mandy Thursday, or Mandate Thursday,
or even Mandatum Thursday; and that the term "Maundy" comes in fact from the
Latin mendicare, Old French mendier, and English maund, which as a verb means
to beg and as a noun refers to a small basket held out by maunders as they maunded.
The name Maundy Thursday thus arose from a medieval custom whereby the English
royalty handed out "maundy purses" of alms to the poor before attending Mass
on this day.

Use of the names "Maundy Thursday",
"Holy Thursday" and the others is not evenly distributed. What is considered
the normal name for the day varies according to geographical area and religious
allegiance. Thus, while in England "Maundy Thursday" is the normal term, this
term is almost never used in Ireland. The same person may use one term in a
religious context and another in the context of the civil calendar of the country
in which he lives.
The Anglican Church uses the name "Maundy
Thursday" in the Book of Common Prayer, where it treats "Holy Thursday" as an
alternative name for Ascension Day. But outside of the official texts of the
liturgy, Anglicans sometimes apply the name "Holy Thursday" to the day before
Good Friday.
The Roman Catholic Church, even in countries
where "Maundy Thursday" is the name in civil legislation, uses the name "Holy
Thursday" in its official English-language liturgical books; but, except in
these texts, Roman Catholics will sometimes use "Maundy Thursday", especially
in England.

The Methodist Church uses the name "Holy
Thursday" in its UM Book of Worship, but in other official sources it both "Maundy
Thursday" and "Holy Thursday".
Both names are used by other Christian
denominations as well, including the Lutheran Church or the Reformed Church.
In the Eastern Orthodox Church, the name
for the holy day is, in the Byzantine Rite, "Great and Holy Thursday" or "Holy
Thursday", and in Western Rite Orthodoxy "Maundy Thursday", "Holy Thursday"
or both.
In the Maronite Church and the Syriac
Orthodox Church, the name is "Thursday of Mysteries".
"Maundy Thursday" is the official name
in the civil legislation of England and the Philippines.

The day has also been known in English
as Sheer Thursday, from an obsolete word shere (meaning "clean" or
"bright"). This name might refer to the act of cleaning, or to the
fact that churches would switch liturgical colors from the dark tones of Lent,
or because it was customary to shear the beard on that day, or for a combination
of reasons. This name is a cognate to the word still used throughout Scandinavia,
such as Swedish "Skärtorsdag", Danish "Skærtorsdag",
Norwegian "Skjærtorsdag", Faroese "Skírhósdagur"
and "Skírisdagur" and Icelandic "Skírdagur".
Skär in Swedish is also an archaic word for wash.
For Eastern Orthodox and Eastern Catholic
Christians this day is referred to liturgically as Holy and Great Thursday,
but is also known, less formally, as Great Thursday or Holy Thursday.
Some secular communities refer to the
day as "Easter Thursday", although technically, the correct day for
this name is the following Thursday, after Easter.

The name "Shire Thursday" is explained
in "Festival" printed by Wynkyn de Worde in 1511:
"Yf a man aske why Shere Thursday is called so, ye may saye that in Holy
Churche it is called (Cena Domini) our Lordes Souper daye; for that day he souped
with this Discyples openly; and after souper he gave them his flesshe and his
blode to ete and drynke. It is also in Englysshe called Sher Thursdaye, for
in olde faders dayes the people wold that daye sher there heedes, and clyppe
theyr berdes, and poll theyr heedes, and so make them honest ayenst Ester Day."