The bombers targeted three Tube trains and the Number 30 bus
Families of 7/7 victims have expressed fury after the suicide attackers were called "apparent bombers" in court.
The hearing, at the Royal Courts of Justice, was to decide how coroners' inquests into deaths from the 2005 Tube and bus bombings should proceed.
But bereaved relatives took offence when Hugo Keith QC used the phrase "apparent" to describe the attackers. He later apologised for the distress.
Ernest Adams, whose son was killed, said it was "upsetting and insulting".
James Adams, 32, a mortgage broker from Cambridgeshire, was among 26 killed by Jermaine Lindsay, 19, on a Tube between King's Cross and Russell Square.
His father Mr Adams, 72, stood up in court and said: "For more than four-and-a-half years, the whole world has known that four sick and evil men killed 52 innocent people.
"And yet now lawyers are talking and writing about 'apparent bombers'."
"Your inquest is not going to be about 52 apparent deaths, it will be about 52 real deaths caused by four real bombers.
"I find it very upsetting and insulting to use the word 'apparent'."
Hazel Webb, whose 29-year-old daughter Laura, of Islington, north London, was one of six people killed at Edgware Road, agreed.
Apologies for distress
She said: "'Apparent bombers' just does not rest easily with me."
Apologising, Mr Keith said: "I must balance that which may seem to be obvious with not wishing to pre-judge the issues.
"We are acutely aware that this raises terrible issues for the bereaved families."
The coroner, Lady Justice Hallett, repeated the apology and said they would come up with another term that would not cause distress.
Suicide bombers Mohammad Sidique Khan, Shehzad Tanweer, Hasib Hussain and Jermaine Lindsay detonated the bombs on three Tube trains and a bus during the morning rush-hour on 7 July 2005, killing 52 people and injuring more than 700.
All the bombers had strong links to West Yorkshire. Khan, Tanweer and Hussain had lived in the Beeston area of Leeds and Lindsay spent his childhood in Huddersfield.
Inquest hearings have not taken place yet because criminal proceedings relating to the attacks have taken years.
Inquest ruling due
Thursday's hearing was told that if full inquests into the deaths are held they are expected to take place in the autumn.
A further three-day hearing, scheduled to begin on 26 April, will decide if full inquests are needed and what their remit should be.
The coroner will then rule whether to split the inquests into the victims' deaths and those of the bombers.
Imran Khan, representing the families of Mohammad Sidique Khan and Hasib Hussain, said: "Whatever involvement my clients have in these proceedings, we will try our utmost to ensure that it is done with sensitivity and deference to the wishes of the bereaved families."
It is thought none of the families of the suicide bombers has applied for legal aid.