What is the difference between a software engineer and web developer?

i have noticed that companies like google and most of the fortune 500 tech companies seems to respect a software engineer more than a web developer. I have been on linkedin for quite some time and i have never seen a job description that says "web developer at google" or "web developer at facebook" they all seem to be "software engineer at google" etc. Is that being a web developer is down played in this companies.