Why is the caption at the built number 641.645 "macadamia nuts--cooking" instead of the more general caption "nuts--cooking"? 

This is one reason it is important to check Relative Index terms for built numbers.  Both "macadamia nuts" and "nuts--cooking" are Relative Index terms at 641.645.  Currently, the first alphabetical Relative Index term is used as a caption for built numbers. 

Also note that there is no specific number for macadamia nuts; it is a concept in standing room at broader numbers.  If you do a broad search on "macadamia" in the All Fields index in WebDewey, you will retrieve hits at the following concepts:

583.89 *Proteales -- ("Macadamia nuts--botany" included as a Relative Index term at this number, along with many other terms)

634.5 Nuts ("Macadamia nuts--agriculture" included as a Relative Index term at this number, along with "Nuts--orchard crop")

B 641.345 Macadamia nuts, . . . ("Macadamia nuts" and "Macadamia nuts--food" included as a Relative Index term at this number, along with "Nuts--food")

B 641.645 Macadamia nuts--cooking, . . . ("Macadamia nuts--cooking" included as a Relative Index term at this number, along with "Nuts--cooking")

See also "Check Your Terms at the Door". 

Last revised: 31 January 2004