MonthName
Purpose 
Returns the full name of the month for date.
Format 
MonthName(date)
Parameters 
date - any calendar date
Data type returned 
text
Originated in 
FileMaker Pro 6.0 or earlier
Examples 
MonthName(“6/6/2014”) returns June.
“Payment due by the end of: ” & MonthName(Date(Month(InvoiceDate) + 1;Day(InvoiceDate);Year(InvoiceDate))) returns Payment due by the end of May, where InvoiceDate is 4/4/2014.
“Payment for: ” & MonthName(Date(Month(Payment) + 1;Day(Payment);Year(Payment))) returns Payment for: followed by the name of the month that is one past the month of the last payment.
Important  To avoid errors when using dates, always use four-digit years. For more information about how FileMaker Pro handles two-digit dates, see Conversion of dates with two-digit years.
Related topics 
Functions reference (category list)
Functions reference (alphabetical list)
About formulas
About functions
Defining calculation fields
Using operators in formulas