Via AWOL and AMIR, several digitized books of linguistic and scholarly interest:
The Jewish National and University Library Digitized Book Repository
Oriental Institute Demotic Dictionary
Arabic Dictionaries:
al-Jawharî: Tâj al-lugha wa-sihâh al-‘arabiyya
Ibn Manzûr, Lisân al-‘arab
az-Zabîdî, Tâj al-‘arûs
al-Azharî, Tahdhîb al-lugha