In the picture framing

Picture frame

A picture frame is a decorative edging for a picture, such as a painting or photograph, intended to enhance it, make it easier to display, or protect it.-Construction:...

 industry, a fillet (also referred to as a slip) is a small piece of moulding which fits inside a larger frame or, typically, underneath or in between matting

Mat (picture framing)

In the picture framing industry, a mat is a thin, flat piece of paper-based material included within a picture frame, which serves as additional decoration and to perform several other, more practical functions, such as separating the art from the glass...

, used for decorative purposes. The picture framing term is probably related to, though not necessarily derived from, the engineering term

Fillet (mechanics)

In mechanical engineering, a fillet is a concave easing of an interior corner of a part design. A rounding of an exterior corner is called a "round" or a "chamfer".-Applications:...

, which it is frequently pronounced similarly to; however, unlike the use of fillets in mechanical engineering, the use of "fillets" in picture frames is wholly decorative.

Pronunciation

Fillet can be pronounced in two ways. One way is to pronounce it as if it were "fill-it", as the similar term from mechanical engineering is pronounced. The other is similar to the French-derived culinary term

Fillet (cut)

A fillet is a cut or slice of boneless meat or fish.- Meat :In the case of beef, in the USA, the term most often refers to beef tenderloin, especially filet mignon.- Chicken :...

 (Fil-lay). Either is acceptable in English, though most frame shops prefer one or the other pronunciation.

NPGHS

Construction

Fillets are typically made of soft or hard wood, and feature a flat "lip" which can fit underneath a mat

Mat (picture framing)

In the picture framing industry, a mat is a thin, flat piece of paper-based material included within a picture frame, which serves as additional decoration and to perform several other, more practical functions, such as separating the art from the glass...

; the non-lip portion is what is displayed. Except for their shape and size (which is understandably small), fillets are constructed similarly to picture frames, usually from wood or polystyrene. Metal fillets are very rare. Fillets are available in a number of styles and finishes, including gold

Gold leaf

right|thumb|250px|[[Burnishing]] gold leaf with an [[agate]] stone tool, during the water gilding processGold leaf is gold that has been hammered into extremely thin sheets and is often used for gilding. Gold leaf is available in a wide variety of karats and shades...

 and silver leafed finishes.

Uses

The fillet is normally used as decoration in the lining of a picture frame

Picture frame

A picture frame is a decorative edging for a picture, such as a painting or photograph, intended to enhance it, make it easier to display, or protect it.-Construction:...

 or underneath a mat inside one; the intent is to help draw the eye inwards to the document being framed.

However, one can also use inverted fillets as form of picture frame on small, flat objects, as seen below:

In this case, the card was glued to the lip of the inverted fillet (which is thus hidden behind the back of the card).

Objects such as this that have been framed using inverted fillets can be backed and then affixed to wire for hanging, displayed on an easel

Easel

An easel is an upright support used for displaying and/or fixing something resting upon it.-Etymology:The word is an old Germanic synonym for donkey...

, or used inside of a larger shadowbox

Picture frame

A picture frame is a decorative edging for a picture, such as a painting or photograph, intended to enhance it, make it easier to display, or protect it.-Construction:...

display. It is important to note that only very small, extremely flat objects can be framed using only an inverted fillet, as a fillet lacks the depth of a traditional picture frame, and due to its size, weight and construction, could not support a great amount of weight on its own.