Yes, I did say I would not choose core hours in any case, since that is not asked here.
To be clear, I do view all answers from Barbara on down as valid suggestions. My agreement is based on the ease of referencing that term (I could pull up another dozen references for it).
From the City of London (link cannot be given since it is a downloadable PDF):
"The Flexitime bandwidth is the span of time within which employees may gain Flexitime credit. The Flexitime bandwidth is 8am to 9:15am and 5:00pm to 6:00pm. Chief Officers have the discretion to vary the Flexitime bandwidth for their department, or larger divisions of their department based on the department’s standard operating hours, however the total bandwidth should not exceed 10 hours. The bandwidth can not be varied for individuals."
US (even used in the 1990s already):
"Bandwidth - the time during which employees may be on
the job."
http://www.deq.state.or.us/nwr/ECO/docs/workhours.pdfWho am I to argue with British and American authorities?