Related Rule
Australia
Practice Relating to Rule 9. Definition of Civilian Objects
Australia’s Defence Force Manual (1994) states:
530 – [The 1977 Additional Protocol I] defines “civilian objects” as all objects which are not military objectives.
916 – Civilian property or objectives are defined as anything which are not military objectives. 
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, §§ 530 and 916.
Australia’s LOAC Manual (2006) states:
5.34 [The 1977 Additional Protocol I] defines “civilian objects.” as all objects which are not military objectives.
9.16 Civilian property or objectives are defined as anything that are not military objectives. 
Australia, The Manual of the Law of Armed Conflict, Australian Defence Doctrine Publication 06.4, Australian Defence Headquarters, 11 May 2006, §§ 5.34 and 9.16.
The LOAC Manual (2006) replaces both the Defence Force Manual (1994) and the Commanders’ Guide (1994).