centre
(=center)
(1)中心，中央
(2)定中心

• attraction
• attraction power
• attractive force
• attribute
• attrition
• attune
• auburn
• Audio
• audio frequency
• audiogram
• audiolocator
• Audiometer
• audion
• Audiovisual
• audio-visual instrument
• Au-doped
• Auer burner
• augend
• Auger Effect
• Auger recombination
• Auger transition
• augment
• augmented matrix
• Augustin Jean Fresnel
• aural