ei·cos·a·noid [ī-'kō-sə-,nȯid] -n

  1. any of a class of compounds (as the prostaglandins) derived from polyunsaturated fatty acids (as arachidonic acid) and involved in cellular activity

ei·co·sa·pen·ta·e·no·ic acid [,ī-kō-sə-,pen-tə-ē-'nō-ik-] -n

  1. an omega-3 fatty acid C 20H 30O 2found esp. in fish oils

ei·der ['ī-dər] -n

  1. any of several large northern sea ducks (genera Somateriaand Polystica) having fine soft down that is used by the female for lining the nest called also eider duck
  2. eiderdown

ei·der·down [-,dau̇n] -n

  1. the down of the eider
  2. a comforter filled with eiderdown
  3. a soft lightweight clothing fabric knitted or woven and napped on one or both sides

ei·det·ic [ī-'de-tik] -adj, adv

  1. marked by or involving extraordinarily accurate and vivid recall esp. of visual images
    • an eidetic memory

ei·do·lon [ī-'dō-lən] -n

  1. an unsubstantial image : phantom
  2. ideal

ei·gen·mode ['ī-gən-,mōd] -n

  1. a normal mode of vibration of an oscillating system

ei·gen·val·ue ['ī-gən-,val-(,)yü] -n

  1. a scalar associated with a given linear transformation of a vector space and having the property that there is some nonzero vector which when multiplied by the scalar is equal to the vector obtained by letting the transformation operate on the vector
  2. a root of the characteristic equation of a matrix

ei·gen·vec·tor [-,vek-tər] -n

  1. a nonzero vector that is mapped by a given linear transformation of a vector space onto a vector that is the product of a scalar multiplied by the original vector called also characteristic vector

eight ['āt] -n, adj, pron, pl in constr

  1. the eighth in a set or series
    • the eight of spades
  2. : something having eight units or members: as
  3. an 8-oared racing boat or its crew
  4. an 8-cylinder engine or automobile

eight ball -n

  1. a black pool ball numbered 8
  2. misfit

eight·fold ['āt-,fōld, -'fōld] -adj, adv

  1. having eight units or members
  2. being eight times as great or as many
    • an eightfold increase

eightfold way -n

  1. a unified theoretical scheme for classifying the relationship among strongly interacting elementary particles on the basis of isospin and hypercharge

eighth ['ātth, 'āth] -n, adj or adv

  1. octave

eighth note -n

  1. a musical note with the time value of of a whole note

eighth rest -n

  1. a musical rest corresponding in time value to an eighth note

eight·pen·ny nail [,āt-,pe-nē-] -n

  1. a nail typically 2 inches (6.35 centimeters) long

eighty ['ā-tē] -n, adj or n, adj, pron, pl in constr

  1. the numbers 80 to 89
  2. the years 80 to 89 in a lifetime or century

eightysix [,ā-tē-'siks] -vt

  1. to refuse to serve (a customer)
  2. to get rid of : throw out

ein·korn ['īn-,kȯrn] -n

  1. an ancient wheat ( Triticum monococcum) having one-grained spikelets and grown esp. formerly in poor soils in central and southern Europe and southwest Asia

ein·stei·ni·um [īn-'stī-nē-əm] -n

  1. a radioactive element produced artificially

ei·re·nic [ī-'re-nik, -'rē-] -adj, adv

(variant of irenic)

  1. favoring, conducive to, or operating toward peace, moderation, or conciliation

eis·ege·sis [,ī-sə-'jē-səs, 'ī-sə-,] -n

  1. the interpretation of a text (as of the Bible) by reading into it one's own ideas

ei·stedd·fod [ī-'steth-,vȯd, ā-] -n, adj

  1. a usu. Welsh competitive festival of the arts esp. in poetry and singing

eis·wein ['īs-,wīn, -,vīn] -n

  1. a sweet German wine made from grapes that have frozen on the vine
  2. a similar wine made elsewhere

ei·ther ['ē-thər also 'ī-] -adj

  1. being the one and the other of two : each
    • flowers blooming on either side of the walk
    • plays either instrument well
  2. being the one or the other of two
    • take either road

either -pron

  1. the one or the other
    • take either of the two routes
  2. used as a function word before two or more coordinate words, phrases, or clauses joined usu. by or to indicate that what immediately follows is the first of two or more alternatives
    • can be used either as a guest room or as an office
  3. likewise, moreover used for emphasis after a negative
    • not smart or handsome either
  4. for that matter used for emphasis after an alternative following a question or conditional clause esp. where negation is implied
    • who answers for the Irish parliament? or army either? -- Robert Browning

ei·theror [,ē-thər-'ȯr also ,ī-] -n

  1. an unavoidable choice or exclusive division between only two alternatives

eitheror -adj

  1. of or marked by either-or : black-and-white