Useful Dictionaries
In your learning of the deciphering of the early-modern Spanish handwriting styles or scripts, consulting words for their meaning is a regular part of the process. The following are probably the two best online dictionaries you may count on, in general, for that task.
"Diccionario de la Real Academia Española" (DRAE) Online
Definitely the most authoritative dictionary you may consult on Spanish vocabulary, available at your fingertips online. For your Spanish paleography learning in general, a fundamental tool. It will help you to reduce your guessing about the letters and the spelling when coming across an unknown word for the first time in a manuscript. In general, if you do not find in the DRAE the spelling you think you are seeing (or the alternate spellings you may wonder about), chances are you are not identifying and deciphering the text adequately. Yet, there is also the possibility that you may be in front of an old term or spelling variance that has not been include in the DRAE. In this last type of case, your best option is trying with a dictionary specializing in old Spanish or regional or national variations of language. To access DRAE press the following link: DRAE.
"Nuevo Tesoro Lexicográfico de la Lengua Española"
An online database of Spanish dictionaries dating from 1729 which shows the oldest printed registers of the words. Excellent supplement in searching for words no longer cited in the DRAE. To access it, press this link: http://ntlle.rae.es/ntlle/SrvltGUISalirNtlle. Once you enter the page, click on "Aceptar" and then go with your mouse to the upper left edge of the page. To the right of the acronym NTLLE located on the left upper angle, click the first icon that reads "Realización de consulta." This will open the search page for you to look up the word you are searching for.