1.  A representation in sculpture or in painting of the cross with Christ hanging on it. [1913 Webster]
" Generally, the Trinity is represented, the Father as an elderly man fully clothed, with a nimbus around his head, and holding the cross on which the Son is represented as crucified, the Holy Spirit descending in the form of a dove near the Son's head. Figures of the Virgin Mary and of St. John are often placed near the principal figures." [1913 Webster]
"Savior, in thine image seen
Bleeding on that precious rood." [1913 Webster]

2.  A measure of five and a half yards in length; a rod; a perch; a pole. [1913 Webster]

3.  The fourth part of an acre, or forty square rods. [1913 Webster]

rood, n.
1 a crucifix, esp. one raised on a screen or beam at the entrance to the chancel.
2 a quarter of an acre.

Idiom:
rood-loft a gallery on top of a rood-screen. rood-screen a wooden or stone carved screen separating nave and chancel.

Etymology:
OE rod

N  rite, ceremony, ritual, liturgy, ceremonial, ordinance, observance, function, duty, form, formulary, solemnity, sacrament, incantation, service, psalmody, ministration, preaching, preachment, predication, sermon, homily, lecture, discourse, pastoral, baptism, christening, chrism, circumcision, baptismal regeneration, font, confirmation, imposition of hands, laying on of hands, ordination, excommunication, Bar Mitzvah, Bas Mitzvah, Bris, Eucharist, Lord's supper, communion, the sacrament, the holy sacrament, celebration, high celebration, missa cantata, asperges, offertory, introit, consecration, consubstantiation, transubstantiation, real presence, elements, mass, high mass, low mass, dry mass, matrimony, burial, visitation of the sick, seven sacraments, impanation, subpanation, extreme unction, viaticum, invocation of saints, canonization, transfiguration, auricular confession, maceration, flagellation, sackcloth and ashes, penance, telling of beads, processional, thurification, incense, holy water, aspersion, relics, rosary, beads, reliquary, host, cross, rood, crucifix, pax, pyx, agnus Dei, censer, thurible, patera, eileton, Holy Grail, prayer machine, prayer wheel, Sangraal, urceus, ritualism, ceremonialism, sabbatism, sabbatarianism, ritualist, sabbatarian, holyday, feast, fast, Sabbath, Pentecost, Advent, Christmas, Epiphany, Lent, Passion week, Holy week, Easter, Easter Sunday, Whitsuntide, agape, Ascension Day, Candlemas, Ash Wednesday, Good Friday, Holy Thursday, Lammas, Martinmas, Michaelmas, All SAint's DAy, All Souls' Day, Ramadan, Ramazan, Bairam Passover, Shabuoth, Yom Kippur, Day of Atonement, Rosh Hashana, New Year, Hanukkah, Chanukkah, Feast of Lights, Purim, Feast of lots, ritual, ritualistic, ceremonial, baptismal, eucharistical, paschal, what art thou, thou idol ceremony?.

N  length, longitude, span, mileage, distance, line, bar, rule, stripe, streak, spoke, radius, lengthening, prolongation, production, protraction, tension, tensure, extension, line, nail, inch, hand, palm, foot, cubit, yard, ell, fathom, rood, pole, furlong, mile, league, chain, link, arpent, handbreadth, jornada, kos, vara, astronomical unit, AU, light- year, parsec, nanometer, nm, micron, micrometer, millimicron, millimeter, mm, centimeter, cm, meter, kilometer, km, pedometer, perambulator, scale, long, longsome, lengthy, wiredrawn, outstretched, lengthened, sesquipedalian, interminable, no end of, macrocolous, linear, lineal, longitudinal, oblong, as long as my arm, as long as today and tomorrow, unshortened &c (shorten), lengthwise, at length, longitudinally, endlong, along, tandem, in a line, in perspective, from end to end, from stem to stern, from head to foot, from the crown of the head to the sole of the foot, from top to toe, fore and aft.

rood screen