(1) “Teacher” shall include all professional employes and temporary professional employes, who devote fifty per centum (50%) of their time, or more, to teaching or other direct educational activities, such as classroom teachers, demonstration teachers, museum teachers, counsellors, librarians, school nurses, dental hygienists, home and school visitors, and other similar professional employes and temporary professional employes, certificated in accordance with the qualifications established by the State Board of Education.

(2) “Service increments” shall mean increases in annual salary granted to all professional employes by reason of their years of service in the school district or career and technical school district.

(3) “Standard certificate” shall mean any one of the following certificates: permanent State certificate, State Normal School certificate, State Normal School diploma, temporary standard certificate, permanent standard certificate, State standard limited certificate, temporary extension standard certificate, permanent extension standard certificate.

(4) “College certificate” shall mean a college provisional certificate, a college permanent certificate, or its equivalent.

(5) “Master's Degree” shall mean a degree secured at a college or university approved by the Department of Education.

The State Board of Education shall establish equivalents for both college certificates and master's degrees. In determining the equivalents, in the case of teachers of applied arts and career and technical subjects, the State Board of Education shall give due consideration to practical experience in the field taught.