Directional pattern (for a sound source or receiver and for a specified frequency band)
A description, generally presented graphically, of a characteristic value of the emission of the source or of the response of the receiver as a function of the direction in a specified plane through a specified point (if possible the acoustic centre).
Note: 1 This definition includes the weighted sound level indicated by a sound level meter.
Note: 2 In the case of the sound source the term Directional radiation pattern is used. In the case of the sound receiver, the term Directional response pattern is used.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM