Public Sub Test()
'Call this procedure from one of the events "Selection Change", "Double Click" etc
Dim iCount As Integer
Dim sOutput As String
Dim iLength As Integer
Dim sWord As String
Dim oTarget As Range
'Place a sentence in cell "A1" and bold a couple individual words in the sentence
Set oTarget = ActiveSheet.Range("A1")
For iCount = 1 To Len(oTarget.Value)
'Bold could be italics, underline, color or whatever to highlight target words
If oTarget.Characters(iCount, 1).Font.Bold = True Then
sWord = sWord & oTarget.Characters(iCount, 1).Text
Else
If sWord <> "" Then sOutput = sOutput & sWord & ","
'Add "sWord" to a list box here
sWord = ""
End If
Next iCount
'Allow user to select word in list box and lookup and display definition for word
If sOutput <> "" Then
MsgBox "Add the following words to drop down list: " & Left(sOutput, (Len(sOutput) - 1)) 'Remove trailing comma
End If
End Sub