As for dictionaries, I must leak a little secret about them to you; they usually come in "number of words", so we can talk about 45,000-word dictionaries (generally, the English-Portuguese dictionaries we see in Brazilian junior high schools - for example).
Those dictionaries sometimes are a bit limited.
An Advanced Larousse increases this contents to 90,000 words and sentences, and some whopping 120,000 translations!http://www.estantevirtual.com.br/marcul ... -101833854
Some dictionaries online can enlarge the query and may have what you want, or you may have it in some other dictionary.
There are also sites with transalation-related questions, like Bab.la, Linguee, Reverso, Wordreference, Kudoz and many more.
You can combine them, you can copy and paste definitions in English, and them use some English-Portuguese dictionary or Google translator to get it into Portuguese.