NOUN (1)

1. a consonant that is articulated using both lips; /p/ or /b/ or /w/;


ADJECTIVE (1)

1. of or relating to or being a speech sound that is articulated using both lips;
- Example: "bilabial fricatives"

The Collaborative International Dictionary of English v.0.48:

bilabial \bi*la"bi*al\ adj. (Linguistics)
   produced using both lips; -- said of a consonant. As,
   bilabial fricatives. See labial, adj. and {bilabial, n.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

bilabial \bi*la"bi*al\ n. (Linguistics)
   a consonant that is articulated using both lips, as p or b or
   w.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

bilabial
    adj 1: of or relating to or being a speech sound that is
           articulated using both lips; "bilabial fricatives"
    n 1: a consonant that is articulated using both lips; /p/ or /b/
         or /w/

Moby Thesaurus II by Grady Ward, 1.0:

125 Moby Thesaurus words for "bilabial":
   accented, allophone, alveolar, apical, apico-alveolar,
   apico-dental, articulated, articulation, aspiration, assimilated,
   assimilation, back, barytone, broad, cacuminal, central, cerebral,
   check, checked, close, consonant, consonantal, continuant, dental,
   diphthong, dissimilated, dissimilation, dorsal, epenthetic vowel,
   explosive, flat, front, glide, glossal, glottal, glottalization,
   guttural, hard, heavy, high, intonated, labial, labialization,
   labiodental, labiovelar, laryngeal, lateral, lax, light, lingual,
   liquid, low, manner of articulation, mid, modification,
   monophthong, monophthongal, morphophoneme, mute, muted, narrow,
   nasal, nasalized, occlusive, open, oxytone, palatal, palatalized,
   parasitic vowel, peak, pharyngeal, pharyngealization,
   pharyngealized, phone, phoneme, phonemic, phonetic, phonic, pitch,
   pitched, plosive, posttonic, prothetic vowel, retroflex, rounded,
   segmental phoneme, semivowel, soft, sonant, sonority, speech sound,
   stop, stopped, stressed, strong, surd, syllabic, syllabic nucleus,
   syllabic peak, syllable, tense, thick, throaty, tonal, tonic,
   transition sound, triphthong, twangy, unaccented, unrounded,
   unstressed, velar, vocable, vocalic, vocoid, voice, voiced,
   voiced sound, voiceless, voiceless sound, voicing, vowel,
   vowellike, weak, wide