A grapefruit knife is a special type of knife

Knife

A knife is a cutting tool with an exposed cutting edge or blade, hand-held or otherwise, with or without a handle. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools...

 designed specifically for cutting grapefruit

Grapefruit

The grapefruit , is a subtropical citrus tree known for its sour fruit, an 18th-century hybrid first bred in Barbados. When found, it was named the "forbidden fruit"; it has also been misidentified with the pomelo or shaddock , one of the parents of this hybrid, the other being sweet orange The...

. Grapefruit knives are small with a unique curved serrated blade

Serrated blade

A serrated blade is a type of blade used on saws and on some knives or scissors. It is also known as a dentated, sawtooth, or toothed blade.A serrated blade has a cutting edge that has many small points of contact with the material being cut...

, designed to hug the curves of the grapefruit. This is used to separate the outer edge of the segments from the rim of the fruit. The term "grapefruit knife" can refer to a type of knife with short, serrated twin blades about 2mm apart, used to separate the sides of each section from the dividing membrane. Some grapefruit knives incorporate both types, a double-sided curved blade on one side and the parallel twin blades on the other. When both types are used, the result is an intact-looking fruit with sections which lift out easily - especially if a "grapefruit spoon

Grapefruit spoon

A grapefruit spoon is a utensil usually similar in design to a teaspoon that tapers to a sharp edge or teeth, the intent of the front serration being to separate the flesh of a grapefruit from its rind...

" is used.

English law

An interesting legal case in the English Criminal Courts has held that a grapefruit knife is, in fact, a knife. It is illegal under the Criminal Justice Act 1988 to sell knives to persons under 18. Trading Standards officers of the Royal Borough of Windsor and Maidenhead brought charges in East Berkshire Magistrates' Court against W J Daniel and Company Limited, one of whose employees had sold a grapefruit knife to a test purchaser under the age of 16 on 17 February 2009. The magistrates were persuaded that it is was not, in fact, a knife but a "gadget" and duly dismissed the case. At an appeal in the High Court

High Court of Justice

The High Court of Justice is, together with the Court of Appeal and the Crown Court, one of the Senior Courts of England and Wales...

, Sir Anthony May

Anthony May (judge)

Sir Anthony Tristram Kenneth May, PC is a British judge.On 1 October 2008, he succeeded Sir Igor Judge as President of the Queen's Bench Division. He was called to the Bar in 1967, became a Queen's Counsel in 1979, and a Recorder in 1985. He was appointed to the Queen's Bench Division in 1991,...

 found that this was wrong. Using the definition of "knife" in the Oxford English Dictionary

Oxford English Dictionary

The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...

("A cutting instrument consisting of a blade with a sharpened longitudinal edge fixed in a handle either rigidly, as in a table knife, carving or sheath knife, or with a joint, as in a pocket or clasp knife. The blade is generally of steel, but sometimes of other material, as in the silver fish and fruit knives, the blunt edged paper knife of ivory, wood, etcetera, and the flint knives of early man.") which, he said, accorded with his own understanding, he ruled that a grapefruit knife was indeed a knife within the meaning of the Act and upheld the appeal. The case was remitted to the magistrates to continue the hearing.