A boline, originally spelled bolline, is a ritual white-handled knife that is used for cutting or carving within the circle. It is one of the eight ritual tools of traditional Wicca. It is introduced to a first degree initiate along with the other seven ritual tools, and its use is demonstrated by a second degree initiate during their elevation. In modern Wicca, it is typically used to cut herbs and/or inscribe candles.
The object that is now typically called the 'boline' was originally called 'the white-handled knife' or 'the white-hilted knife', as it was called by Gerald Gardner and Alex Sanders. In Gerald Gardner's book of shadows, he refers to the object as 'the white-handled knife' five times, and as 'the white-hilted knife' once, and there is no mention of a boline. In Alex Sanders' book of shadows, he refers to the object as 'the white-handled knife' once, and as 'the white-hilted knife' four times, and only once mentions a 'bolline' (spelled with 2 Ls in this case). Even as late as 1986, in Raymond Buckland's book Buckland's Complete Book of Witchcraft, Buckland doesn't use the word 'boline', but uses the term 'white-handled knife' two times and 'white-hilted knife' once, though in one instance he conflates the white-handled knife with a burin.
Both the white-handled knife and the boline are objects that derive from the Key of Solomon, but they are not the same object. At some point they were conflated with eachother, so that the white-handled knife is now falsely called the boline. The word 'boline' derives from the word 'bolino' from an italian manuscript of the Key of Solomon. The word 'bolino' is a variant spelling of the italian word 'bulino', which means 'burin', which is what the real boline was.
In addition to the conflation of the white-handled knife with the boline, the boline (burin) was conflated with a sickle, which resulted in so-called "bolines" that have curved sickle-like blades. That second conflation was caused by some unidentified influential wiccan who read Arthur Edward Waite's 1911 book The Book of Ceremonial Magic, in which Waite conflates the boline (burin) from the Key of Solomon with the sickle that is mentioned in an italian version of the Key of Solomon. The original Key of Solomon didn't even mention a sickle, but an italian translator misinterpreted the unrecognized latin word "artavus" (meaning "quill knife") as a sickle ("falcetto" in italian).
An alternate spelling of "boline" or "bolline" is "boleen".
The spelling "boleen" was inadvertantly invented by a wiccan with the craft name 'Wren', who heard the word 'boline' spoken but did not know how it was spelled, so she wrote the word "boleen" in an article on the major wiccan website WitchVox in july of 2000, and from there that false spelling spread. The spelling "boleen" is most often used by people who are unfamiliar with Wicca and thus do not know the correct spelling.
It is unclear when the spelling "boline" (with one L) was first used. Even the neo-wiccan author Silver Ravenwolf uses the original spelling "bolline". The spelling "boline" may have been invented in october of 2002, when the Wikipedia article with that name was created by an anonymous IP edittor, and no one bothered to check the references.