[Koha] how to convert excel files into Koha DB and sndx_word??

Hi, I have a long book list that I need to import into a Koha database. It was originally created in MS Excel format. The easiest way that I come up with was to convert the main excel file into several excel files and import into the Koha database using a MySQL tool. I've already managed the conversion except one table, marc_word. I couldn't figure out the last column of this table. Is there a source that teaches what "sndx_word" means? And, how can I create it? If anybody also knows easier way to convert an excel table into a Koha DB, I'll really appreciate the help. Thank you. Ahmet Sanli