The Collaborative International Dictionary of English v.0.48:

Holy \Ho"ly\, a. [Compar. Holier; superl. Holiest.] [OE.
   holi, hali, AS. h[=a]lig, fr. h[ae]l health, salvation,
   happiness, fr. h[=a]l whole, well; akin to OS. h?lag, D. & G.
   heilig, OHG. heilac, Dan. hellig, Sw. helig, Icel. heilagr.
   See Whole, and cf. Halibut, Halidom, Hallow,
   Hollyhock.]
   1. Set apart to the service or worship of God; hallowed;
      sacred; reserved from profane or common use; holy vessels;
      a holy priesthood. "Holy rites and solemn feasts."
      --Milton.
      [1913 Webster]

   2. Spiritually whole or sound; of unimpaired innocence and
      virtue; free from sinful affections; pure in heart; godly;
      pious; irreproachable; guiltless; acceptable to God.
      [1913 Webster]

            Now through her round of holy thought
            The Church our annual steps has brought. --Keble.
      [1913 Webster]

   Holy Alliance (Hist.), a league ostensibly for conserving
      religion, justice, and peace in Europe, but really for
      repressing popular tendencies toward constitutional
      government, entered into by Alexander I. of Russia,
      Francis I. of Austria, and Frederic William III. of
      Prussia, at Paris, on the 26th of September, 1815, and
      subsequently joined by all the sovereigns of Europe,
      except the pope and the king of England.

   Holy bark. See Cascara sagrada.

   Holy Communion. See Eucharist.

   Holy family (Art), a picture in which the infant Christ,
      his parents, and others of his family are represented.

   Holy Father, a title of the pope.

   Holy Ghost (Theol.), the third person of the Trinity; the
      Comforter; the Paraclete.

   Holy Grail. See Grail.

   Holy grass (Bot.), a sweet-scented grass (Hierochloa
      borealis and Hierochloa alpina). In the north of Europe
      it was formerly strewed before church doors on saints'
      days; whence the name. It is common in the northern and
      western parts of the United States. Called also vanilla
      grass or Seneca grass.

   Holy Innocents' day, Childermas day.

   Holy Land, Palestine, the birthplace of Christianity.

   Holy office, the Inquisition.

   Holy of holies (Script.), the innermost apartment of the
      Jewish tabernacle or temple, where the ark was kept, and
      where no person entered, except the high priest once a
      year.

   Holy One.
      (a) The Supreme Being; -- so called by way of emphasis. "
          The Holy One of Israel." --Is. xliii. 14.
      (b) One separated to the service of God.

   Holy orders. See Order.

   Holy rood, the cross or crucifix, particularly one placed,
      in churches. over the entrance to the chancel.

   Holy rope, a plant, the hemp agrimony.

   Holy Saturday (Eccl.), the Saturday immediately preceding
      the festival of Easter; the vigil of Easter.

   Holy Spirit, same as Holy Ghost (above).

   Holy Spirit plant. See Dove plant.

   Holy thistle (Bot.), the blessed thistle. See under
      Thistle.

   Holy Thursday. (Eccl.)
      (a) (Episcopal Ch.) Ascension day.
      (b) (R. C. Ch.) The Thursday in Holy Week; Maundy
          Thursday.

   Holy war, a crusade; an expedition carried on by Christians
      against the Saracens in the Holy Land, in the eleventh,
      twelfth, and thirteenth centuries, for the possession of
      the holy places.

   Holy water (Gr. & R. C. Churches), water which has been
      blessed by the priest for sacred purposes.

   Holy-water stoup, the stone stoup or font placed near the
      entrance of a church, as a receptacle for holy water.

   Holy Week (Eccl.), the week before Easter, in which the
      passion of our Savior is commemorated.

   Holy writ, the sacred Scriptures. " Word of holy writ."
      --Wordsworth.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Thursday \Thurs"day\, n. [OE. [thorn]ursdei, [thorn]orsday, from
   the Scand. name Thor + E. day. Icel. [thorn][=o]rr Thor, the
   god of thunder, is akin to AS. [thorn]unor thunder; D.
   Donderdag Thursday, G. Donnerstag, Icel. [thorn][=o]rsdagr,
   Sw. & Dan. Torsdag. [root]52. See Thor, Thunder, and
   Day.]
   The fifth day of the week, following Wednesday and preceding
   Friday.
   [1913 Webster]

   Holy Thursday. See under Holy.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ascension \As*cen"sion\, n. [F. ascension, L. ascensio, fr.
   ascendere. See Ascend.]
   1. The act of ascending; a rising; ascent.
      [1913 Webster]

   2. Specifically: The visible ascent of our Savior on the
      fortieth day after his resurrection. (--Acts i. 9.) Also,
      Ascension Day.
      [1913 Webster]

   3. An ascending or arising, as in distillation; also that
      which arises, as from distillation.
      [1913 Webster]

            Vaporous ascensions from the stomach. --Sir T.
                                                  Browne.
      [1913 Webster]

   Ascension Day, the Thursday but one before Whitsuntide, the
      day on which commemorated our Savior's ascension into
      heaven after his resurrection; -- called also Holy
      Thursday.

   Right ascension (Astron.), that degree of the equinoctial,
      counted from the beginning of Aries, which rises with a
      star, or other celestial body, in a right sphere; or the
      arc of the equator intercepted between the first point of
      Aries and that point of the equator that comes to the
      meridian with the star; -- expressed either in degrees or
      in time.

   Oblique ascension (Astron.), an arc of the equator,
      intercepted between the first point of Aries and that
      point of the equator which rises together with a star, in
      an oblique sphere; or the arc of the equator intercepted
      between the first point of Aries and that point of the
      equator that comes to the horizon with a star. It is
      little used in modern astronomy.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Holy Thursday
    n 1: the Thursday before Easter; commemorates the Last Supper
         [syn: Maundy Thursday, Holy Thursday]