The Australian Senate has descended into debates of word definitions as Australian Greens Senator Scott Ludlam and the nation's Attorney-General Senator George Brandis have once again locked horns in Senate Question Time today.

In response to statements made yesterday by Prime Minister Tony Abbott that metadata is "essentially the billing data", and the prime minister's assertion that there is a large difference between billing data and actual content of calls, Senator Ludlam called upon the attorney-general to school the prime minister in the definition of the term "metadata".

"Metadata reveals mobile and landline phone records, a person's precise location, the source and destination of electronic mail, their entire social networks, your web history — could the attorney please give an undertaking to remind the PM of what this term actually means?" Ludlam asked.

Brandis responded by saying that metadata is a term that means different things to different people, and that during the course of parliamentary inquiries in the last parliament, a number of different witnesses had delivered different definitions of the term metadata.

"I, myself, on the basis of having been informed by the evidence of those several witnesses during the course of the last parliament, thought that the prime minister's description of metadata as 'essentially billing details' was a perfectly accurate shorthand description of what is a contestable concept," the attorney-general said.

Yesterday in the Senate Question Time, Senator Brandis branded NSA whistleblower Edward Snowden an "American traitor" as he responded to reports that the Australian Signals Directorate was willing to share "bulk, unselected, un-minimised metadata" with other members of the Five Eyes intelligence group.

"Those claims are made on the basis of material placed in the public domain by the American traitor Edward Snowden," Brandis said.

"I note that the document of which the report is based is unverified. I also note that the unverified document is described as a draft document, which, contrary to all reports, does not report or record any activity by any Australian intelligence agency."

The attorney-general said that Australian intelligence agencies "operate under a strong framework of legislation, parliamentary, ministerial, and executive oversight", and the government is confident that its intelligence agencies act legally.